Deterministic atom steering for repeated identical defect generation in the scanning transmission electron microscope

Abstract

A system and method are disclosed that use the focused electron beam in a scanning transmission electron microscope (STEM) to deterministically steer a selected atom from its initial position (A) to a final position (B) in a material. This degree of control is achieved by fast and repeated electron beam movement (scanning) of the electron beam between two or more positions and may include fast blanking of the electron beam to exert control over the delivery of electrons in space and time. This method allows deterministic introduction of structural modifications or individual defects to the material. A detector may be used to determine when an atom or atoms have been successfully moved to the final position.

Description

[0001]Deterministic atom steering for repeated identical defect generation in the scanning transmission electron microscope This application claims priority of U.S. Provisional Patent Application Serial No. 63 / 682,129, filed August 12, 2024, the disclosure of which is incorporated by reference in its entirety. Field This disclosure describes embodiments in which atoms in a material are steered or repositioned to new well-defined atomic sites by using precise electron beam control in space and time. Background Atomic defects in solid-state materials are technologically important for a large variety of properties and applications. Examples include defects or dopants in semiconductors that exhibit optical emission properties essential for quantum photonic technologies, high density magnetic storage devices where atomic- scale defects can be used to store data, catalysis where defects enhance catalytic activity, efficiency and selectivity, or unique mechanical properties obtained through the presence of atomic defects. The ability to create atomic defects in specific locations is especially important as it would enable technological advancement across multiple areas. In particular, the placement of optically active defects would trigger a revolution in constructing large scale photonic quantum systems with arbitrary arrangements of nanoscale light emitters. However, strategies for precise creation of atomic scale defects such as vacancies, dopants and interstitials are limited, with a variety of bottlenecks existing for the repeated and fully deterministic generation of identical defects over macroscopical (micrometer) areas. The earliest approach to manipulate a material atom-by-atom was performed using the scanning tunneling microscope (STM). However, atomic manipulation in STM is slow, is confined to conducting surfaces and oftentimes requires low (liquid helium) operation temperature. This significantly limits the range of materials that can be manipulated and the types of properties that can be generated. Therefore, an improved method of steering atoms from a first position to a second known position would be beneficial. Summary A system and method are disclosed that use the focused electron beam in a scanning transmission electron microscope (STEM) to deterministically steer a selected atom from its initial position (A) to a final position (B) in a material. This degree of control is achieved by fast and repeated electron beam movement (scanning) of the electron beam between two or more positions and fast blanking of the electron beam to exert control over the delivery of electrons in space and time. This method allows deterministic introduction of defects to the material. A detector may be used to determine when an atom or atoms have been successfully moved to the final position. According to one embodiment, a method of moving an atom in a material from a first position to a predetermined second position is disclosed. The method comprises using a scanning transmission electron microscope (STEM) to direct an electron beam at the first position; and repeatedly moving the electron beam in a predetermined pattern to displace the atom from the first position and guide it toward the second position within the material. In some embodiments, the predetermined pattern comprises a 1 dimensional (1D) scan. In some embodiments, the predetermined pattern comprises a two dimensional (2D) scan. In certain embodiments, the 2D scan comprises an ellipsoid or an ellipsoid spiral. In some embodiments, the method also includes adjusting an intensity of the electron beam as it moves in the predetermined pattern. In certain embodiments, the intensity is greater near the first position and the second position. In some embodiments, the method includes using a detector to measure a signal sensitive to an atomic structure of the material. In certain embodiments, the signal is used to identify that the atom has been moved to the second position. In certain embodiments, the signal is used to detect errors in atom movement. In certain embodiments, the detector comprises an annular dark field (ADF) detector, an annular bright field (ABF) detector, a bright field (BF) detector, a secondary electron (SE) detector, or photon detectors or charge transport signals. In some embodiments, the material has a crystalline structure. In certain embodiments, the material is one monolayer in thickness. In certain embodiments, the material is up to 100 atoms thick. According to another embodiment, a method of moving one or more first atoms arranged in a first column, each moving from a first position to a second position within a material, and moving one or more second atoms arranged in a second column, each moving from a third position to a fourth position within a material, is disclosed. The method comprises using a scanning transmission electron microscope (STEM) to direct an electron beam to the first position; repeatedly moving the electron beam in a first predetermined pattern to displace the one or more first atoms from the first position and guide them toward the second position; terminating movement of the electron beam in the first predetermined pattern when the one or more first atoms are at the second position within the material; using the STEM to direct the electron beam to one or more second atoms arranged in a second column at a third position; repeatedly moving the electron beam in a second predetermined pattern to displace the one or more second atoms from the third position and guide them toward a fourth position; and terminating movement of the electron beam in the second predetermined pattern when the one or more second atoms are at the fourth position within the material. In some embodiments, a detector is used to measure a signal sensitive to an atomic structure of the material. In certain embodiments, the signal is used to terminate movement of the electron beam in the first predetermined pattern and the second predetermined pattern. In certain embodiments, the signal is used to detect errors in atom movement. In certain embodiments, the detector comprises an annular dark field (ADF) detector, an annular bright field (ABF) detector, a bright field (BF) detector, a secondary electron (SE) detector, or photon detectors or charge transport signals. In some embodiments, the method also includes performing a precision location determination after the one or more first atoms have moved to the second position and before directing the electron beam toward the one or more second atoms. Brief Description of the Drawings For a better understanding of the present disclosure, reference is made to the accompanying drawings, in which like elements are referenced with like numerals, and in which: FIG. 1 shows a flowchart illustrating the disclosed method. FIG. 2 shows a list of beam control jobs according to one embodiment. FIG. 3A-3C show different patterns of electron beam motion between first position (A) and second position (B). FIG. 4 shows the time dependence of a specific beam control pattern, with a repeated motion of the electron beam between the first position (A) and the second position (B). Moreover, the electron beam can be switched off and on by beam blanking to exert additional control of electron delivery in space and time. FIG. 5 shows a cross-sectional view of a crystal illustrating the movement of atoms from a first position (A) to a second position (B). FIG. 6 shows a top view of the exemplary movements of the atoms in moving from first position (A) to second position (B). FIG. 7 is an illustration of the time dependent electron detector read-out for the electron beam placed at two distinct positions. FIG. 8 shows the repeated steering of single or multiple atoms in multiple columns based on a list of beam control jobs. FIG. 9 shows the atomic structure of CrSBr, with atom steering of Cr atoms on multiple layers. FIG. 10 shows the time evolution of the annular dark field detector during periodic fast beam motion between two positions. FIG. 11 shows the position-integrated time evolution of the annular dark field detector for the Cr and SBr atomic columns. FIG. 12 shows the atomic column signal from an ADF detector for an individual experiment as a function of time for movement between three atom columns. FIG. 13 shows experimentally acquired plan view images depicting the movement of Cr atoms in different directions. FIGs. 14-15 show 25 targeted Cr atomic columns in which the atoms have been moved in the b and a directions, respectively. FIG. 16 shows a pattern of atomic displacements created by a series of beam control jobs consisting of six + / -b electron beam motions with one Cr atomic column spacing. FIG. 17 shows distance variation with atomic precision of two + / - b electron beam motions. FIG. 18 shows a cross-sectional view of an atomic thin layer illustrating the ejection of an atom from a first position (A). FIG. 19 shows a cross-sectional view of an atomic thin layer illustrating the movement of an atom from a first position (A) to a second position (B). FIG. 20 shows the results of targeting a single tungsten atom in a WS2layer. FIG. 21 shows the results of targeting two sulfur atoms in a WS2layer, where the full ejection of each sulfur atom is observed at discrete time steps. FIG. 22 shows the results of targeting two sulfur atoms in a WS2layer, where the discrete movement of one sulfur atom under the electron beam without ejection is observed. Detailed Description As noted above, the ability to precisely select and steer an atom is an elusive goal. The aberration corrected scanning transmission electron microscope (STEM), owing to its electron beam focused to a few tens of picometers, provides several advantages in terms of atomic steering. These include the ability to displace atoms in thick materials, the ability to perform this task at room temperature and the speed possible in electron beam scanning that enables real-time control. This provides opportunities to generate very specific atomic rearrangements, known as defects, with preferred properties in bulk materials. Particularly attractive is the potential ability to rearrange large numbers of atoms into arbitrary configurations, with such operation taking place reliably and autonomously. This would enable the properties of the material to be tailored precisely. However, routines for fully deterministic atomic manipulation using the STEM are currently absent. Such operation requires real time monitoring and control of the movement of an atom to a well- defined atomic location with 100% fidelity. Moreover, this task has to be sequentially performed at well-defined atomic locations, for example to create multiple copies of a specific atomic rearrangement or defect in an arbitrary pattern, or create different configurations of atoms in a pattern. Either of these can program a specific property into the material. This disclosure presents a system and method using the focused electron beam in a scanning transmission electron microscope to deterministically steer a selected atom from its initial position (A) to a final position (B) in a material. This degree of control is achieved by fast and repeated electron beam movement (scanning) of the electron beam between two or more positions and fast blanking of the electron beam to exert control over the delivery of electrons in space and time. Scanning is generally referred to as a periodic electron beam motion between 2 or more positions. Scanning may be either periodic or nonperiodic. As an example of such a scan, the beam may be moved continuously between position A and B moving the beam in a one- dimensional (1D) line. Here, positions A and B refer to an atom or atoms or a bond or bonds or another location between atoms and bonds. However, any type of electron beam motion, or scan pattern, can be envisioned. Irradiating one atomic position, A, moves the target atom away from that position. But the exposure of a position or positions different from the target atom or atoms can direct the target atom or atoms at A to specific locations, rather than simply displacing them away from location A to an indeterminate destination. The reason that steering the beam between two or more locations is superior to leaving it in a fixed location is that the beam control pattern may affect one specific bond or group of bonds or excite the electronic system at the target atoms or final position atom or atoms into a non-equilibrium electronic configuration that in turn triggers the movement of the target atom or atoms to a final location. The location (B) may or may not be the location to which the beam moves. Location B may be an interstitial or surface site. FIG. 1 shows the method of moving an atom from a first position (A) to a deterministic second position (B). This method may be performed using a software program in communication with a scanning transmission electron microscope. The software program may be executed by any suitable controller, such as a personal computer, server, special purpose controller, or other device. The software program is stored in a non-transitory computer readable media. This media may be a nonvolatile memory, such as a ROM, FLASH ROM, EEROM, magnetic disk or others. Alternatively, it may be a volatile memory, such as RAM or DRAM. As shown in Box 1, the procedure is started. In Box 2, the electron beam control is initiated. To perform the scan, a variety of parameters may be provided to the software program. These parameters include lattice parameters of the target material, which can be obtained either as user input or from using a deep convolution neural network (DCNN) or fast Fourier transform (FFT) of an experimental STEM image which can be acquired prior to the start of the procedure. The lattice parameters inform the software program as to the crystalline structure of the target material. Additionally, a list of beam control jobs, such as is shown in FIG. 2, may be provided to the software program. As shown in FIG. 2, the list of beam control jobs includes a plurality of entries, each entry including a scan event, the type of scan, and scan logic, such as the starting location, the ending location and the condition used to terminate the scan. In addition to electron beam motions, the list may also include commands to perform a precision location determination. This is done to allow for fully autonomous beam control over extended areas and periods of time. Various techniques may be used to achieve this precision location determination, including “atomic lock-on”, as disclosed in U.S. Patent Application Serial No. 63 / 601,529 and WO2025 / 111178, which are incorporated herein by reference in their entireties. The list may include frequent or infrequent use of these precision location determination routines. Next, as shown in Box 3, the STEM moves the electron beam to the first atom location identified in the list of beam control jobs. Precision location determination is then performed, as shown in Box 4, to ensure proper positioning of the electron beam with respect to the atomic lattice. Positioning may be accurate to within tens of picometers or less, despite distortions or drift that may occur. Examples of techniques to achieve this positioning include the use of atomic lock-on or a deep convolution neural network (DCNN). In Box 5, the electron beam is scanned between the current location and the desired location of the atom (as found in the list of beam control jobs). The electron beam irradiates these locations, delivering energy that changes the bonds and electronic structure locally. A focused electron beam may be used to deliver energy to specific atoms in materials that are very thin, such as a single monolayer (one to a few atoms in thickness, which may be up to, for example, 5 atoms in thickness) and may also be used to deliver energy to all atoms in one column within a thicker material, up to several tens of atoms thick, such as up to 70 atoms thick, due to the process by which the electrons are transmitted through the material. In other words, in certain embodiments, the material comprises a layered structure having between 1 and approximately 100 atomic planes. This includes two-dimensional materials such as graphene, hexagonal boron nitride, transition metal dichalcogenides, chromium sulfide bromide and black phosphorus, which typically comprise between 1 and 7 atomic planes per monolayer. In certain embodiments, multilayer or bulk-like configurations may contain significantly more atoms with 100 or more atomic planes, within a stack, unit cell, or heterostructure. This may include Ruddlesden-Popper phases, layered oxides, or van der Waals superlattices. The present method relies on extremely precise positioning of the electron beam relative to the crystal structure of the material, as explained above. The scanning of the beam between two or more positions has an additional benefit, beyond controlling the destination site. This benefit is that it enables the atomic movement to be monitored. Specifically, the movement of atoms from first position (A) to second position (B) is observable during the scan. During the repeated scanning, the electron detector signal which reflects the number of atoms in the columns is measured. This may, for example, be done using an annular dark field (ADF) detector but may also be measured on an annular bright field (ABF) detector, a bright field (BF) detector, a secondary electron (SE) detector, or any detector that measures a signal sensitive to the atomic structure of the material. This includes detectors measuring low angle scattered transmitted electrons, high angle scattered electrons, diffraction information or energy loss information. This may also include a photon detector that may be a charge coupled device (CDD) that collects photons emitted from the generated atomic modification that may be a defect or multiple defects; or a corresponding charge transport signal from electronic leads attached to the sample. Simultaneous tracking of the detector intensity from the repeated scanning between the two positions may be achieved with a high time resolution, of the order of microseconds. This high time resolution provides the ability to track the occupancy of the atoms within their respective atomic column or other position observed in time and space. Real time control based on user defined conditions may be used to monitor and control the atomic movement, for example terminating the scanning process when the envisioned atomic manipulation is accomplished, which may be sensed by crossing a threshold value on the detector or may be any time- dependent signal measured on the detector. Several different possible electron beam motions (scan patterns) between position A and position B are shown in FIGs. 3A-3C. In terms of the actual scan pattern, this may be a 1D linear scan (FIG. 3A), or 2D scan such as an ellipsoid (FIG. 3B) or more complex scan pattern such as an ellipsoid spiral (FIG. 3C). Of course, other scan patterns that involve arbitrary numbers of locations and time dependent exposure patterns are also possible. Moreover, fast blanking of the electron beam may be used to precisely deliver electrons in space and time by varying the intensity of the electron beam on times in a way that is correlated with the position of the electron beam at that moment in time. The electron beam intensity may be varied by intermittent blanking of the electron beam, changing the beam current or changing the speed of the scan. For example this may be used to selectively deliver energy only on atomic columns, while avoiding bonds, or to otherwise control the local electron dose that specific sites receive. FIG. 4 shows a representative graph, wherein line 40 represents the path of the electron beam as it moves in a 1D scan between first position (A) and second position (B), which the movement of the position of the electron beam as a function of time may have a sinusoidal dependence. The second dotted line represents the blanking of the electron beam. Blanking may be used, for example, to deliver electrons selectively to atoms or bonds. The selective delivery may be used to change the relative dose distribution at different positions. Note that the electron beam has high intensity (42) when near the atomic columns, but is blanked (41) as it passes intermediate sites. As noted above, the electron beam is focused when directed at an atomic column, as the positive nuclei tend to attract the electrons. In contrast, the sites between atoms tend to scatter the electrons in the electron beam to their surroundings, particularly to proximal atom columns, making it more difficult to exactly deliver the electrons and move the atoms and to avoid electron beam damage in the process. Thus, as shown in FIG. 4, the electron beam has high intensity (42) near first position (A) and near second position (B), but is blanked (41) at all other times. Further note that the electron beam may be active for longer periods of time near second position (B), as the electron beam tends to attract the desired atom toward that position. Thus, in addition to the movement of the beam, the intensity of the beam is also controlled during the movement. While this example is for an electron beam motion between two positions, other beam motions with more than 2 positions can be performed. Directing the beam along different crystallographic directions provides the ability to steer the atom or atoms in position A to four different interstitial sites for this specific lattice in the material CrSBr, as shown in FIG. 6. In other words, the atom may be moved in the +y, -y, +x or -x directions that correspond to the +b, -b, +a and -a crystallographic directions. Thes figures show the atom moving from an initial location 12 (A) to a destination location 14 (B). The beam position and delivered electron intensity in time may be completely arbitrarily chosen by the operator to impose a desired effect on the structure. The beam motion may also be directed off the crystallographic axes to steer atoms into other positions, however this may require multiple atomic movements. The process is exemplary for this crystal symmetry but works analogously for other crystal structures and symmetries (two-fold, three-fold etc.). FIG. 5 shows a cross- sectional view of a crystal where the atoms are connected into atomic layers 10 separated by gaps 15. These common types of crystal have gaps 15 due to the particular type of bonding present in the structure. The target atoms (which may be on multiple atomic layers) are initially at their expected position at initial location 12, which may be the first position (A). By repeated electron beam motion between point 11 and point 13, the target atoms are moved to destination location 14. Note that in addition to moving the x or y direction, the atoms may also be moved in the z direction, such as to a location in the gap 15, which may be an interstitial position. Although this is described for van der Waals layered materials, the bonding type can be 3D covalent as well. Further, as noted above, during the scan, the ADF detector may be used. The readout from the ADF detector may be used to monitor the number of atoms in the targeted and final atomic columns so as to track the movement of the atom or atoms from A to B. FIG. 7 shows a representative diagram showing the time-dependent electron detector readout as the atoms are moved from first position (A) to second position (B). Note that the solid line shows the intensity at first location (A), while the dotted line shows the intensity at second position (B). Before the scan begins, the intensity at first position (A) is a maximum 30, while the intensity at second position (B) is at a minimum 32. As the atom is moving from first position (A) to second position (B), the intensity at first position (A) decreases. The solid line in FIG. 7 shows a first step 31, and two additional steps before reaching the minimum 34. However, the intensity at second position (B) (the dotted line) increases during this time, concluding at maximum 33. Note that the data displayed in FIG. 7 is collected only when the electron beam is at first position (A) or second position (B). By monitoring the ADF detector, important information may be gathered. For example, the software program may be programmed to change dose distribution in space and time to move the atom or atoms in response to the real time ADF readout. Additionally, the software may choose to terminate the process based on the ADF detector, such as, for example, when a certain threshold intensity is reached, indicating that a certain number of atoms have been moved. Next, as shown in Box 6 of FIG. 1, the software program checks for test criteria in the outcome and corrects, if necessary. Criteria may be inferred from the time-dependent detector measurement which reflects the atom population in the initial and final column or may be inferred from any type of scan. Following the intensity verification, the software program checks if there are more atoms in the list of beam control jobs to process, as shown in Box 7. If so, the software program causes the STEM to move the electron beam to the next target atom in the list, as shown in Box 9. For sequential jobs during extended operation, the global lock-on (exact lattice position and with it the reference of the electron beam to the target atom and atoms) is maintained by repeating the process to obtain the reference for updating the lattice information at a time interval that depends on the stability of the system during the procedure. The repeatedly updated lattice positions avoid unit cell lattice jump during execution of the list of beam control jobs. If there are no more atoms in the list of beam control jobs, the software program terminates, as shown in Box 8. FIG. 8 shows an illustration where the list of beam control jobs included 9 different target atoms, each with a respective destination. These atoms may be single atoms or multiple atoms in multiple columns. Using the list of beam control jobs, all these target atoms may be moved by the STEM. In certain embodiments, a precision location determination, such as by using atomic lock-on, may be performed one or more time during the 9 scan jobs to ensure the positioning of the electron beam. The frequency of obtaining precision positioning depends on the time spent for each atom movement (for each item in the list of beam control jobs) and the drift rate of the microscope. Having described the method of moving target atoms from a first position (A) to a second position (B), the results of actual procedures will be described. The procedure was demonstrated experimentally using the van der Waals magnetic semiconductor CrSBr, which is shown in FIG. 9. This material exhibits two distinct atomic columns, Cr and SBr, in a plan view projection. Moreover, the material exhibits a van der Waals gap between the layers with interstitial sites. While FIG. 9 shows 4 layers, it is understood that the number of layers of the CrSBr crystalline material is not limited to this embodiment. The Cr atoms are highly mobile under the electron beam and under broad beam illumination are known to move into the van der Waals gap. Atom steering is schematically depicted moving a CR atom from the layer into an interstitial site in the can der Waals gap between the layers using controlled motion of the electron probe. In this experiment, the ADF detector intensity is tracked in space and time for a repeated motion of the electron beam between the Cr and SBr atomic column along the +b direction. FIG. 10 shows the results for a repeated linear scan (beam motion). The top graph shows the intensity 53 over a total time of 1 second. The bottom graph shows an exploded view that includes only 2000 microseconds. This bottom graph shows a round trip time of 200 microseconds, wherein segment 55 shows the time to move from the Cr column to the SBr column along the +b direction. Line 51 corresponds to when the position of the electron beam is aligned with the column of Cr atoms, while line 54 corresponds to the SBr atomic columns. Changes in intensity provide direct information of loss or gain of atoms. The oscillations in the measured ADF detector signal show the evolution of the atomic column intensities in time, allowing for real time monitoring or atomic occupation. As seen in FIG. 11, integrating the ADF detector intensity for times when the electron beam overlaps with the Cr or with the SBr atomic columns allows visualization of the time evolution of both atomic column intensities. Further, as seen in FIG. 11, the atomic column intensities are anti-correlated showing the movement of the Cr atom between the two atomic columns and no loss of atomic species reflecting the atom number conserving nature of the process. The reduction in intensity of the Cr column aligns with the increase of intensity in the SBr column, which indicates movement of at least one Cr atom. This happens in steps with one or multiple atoms moving at once. The step-like behavior of the detector signal shows the movement of the Cr atoms in time. FIG. 12 shows the electron beam movement 60 for repeated + / - b direction motion over three atom columns from SBr to Cr to SBr of an individual experiment. The initial Cr atomic column intensity 61 is shown along with the increase in the intensity 62 of the SBr atomic column due to movement of a Cr atom into this column. Recurring Cr intensity 63 is also shown, which is due to movement back to the original atomic column driven by the electron beam. This figure highlights the real-time measurement of the movement of Cr atoms between the three atom columns as another example of more complex movements that can involve more than 2 atom columns. Any complex scan pattern can be envisioned and the atom population is measured in real-time since the electron beam serves not only as means to move the atom but also to measure its presence. In another experiment, the movement of Cr atoms in four different directions was demonstrated. As shown in FIG. 13, the reduced intensity in the original target Cr position (A) 21 and the increased intensity in the SBr final position (B) 20 demonstrate the movement of the Cr atoms. Each graph shows a brightened area that corresponds to the final destination of the Cr atoms. Additionally, the list of beam control jobs and the real time position tracking may be used to perform repeated movements of atoms and atom columns over extended length areas to scale up material modification. FIG. 14 shows a “+ / -b” linear scan at each site, to move Cr atoms in two proximal SBr columns for 25 individual positions, while FIG. 15 shows a “+ / -a” linear scan. The execution took less than 50 seconds, where the time per defect structure is about 2 seconds. In some embodiments, this time may be dramatically reduced by calculating the necessary amount of electron dose needed for creating the desired structure. This may be adjusted by changing scan speed or by changing the amount of beam current emitted by the STEM. The process was also shown to closely pack the defects in a 1D line by arranging six + / -b beam motions that are only spaced apart by one Cr atomic column, as shown in FIG. 16. This figure shows two vertically stacked 1D arrangements of six + / -b scans with 1 CR atom column spacing. Moreover, as shown in FIG. 17, deliberate atomic spacings were demonstrated, changing the distance between + / -b beam motions by increments of Cr atomic columns from no spacing to a spacing of 5 demonstrating the atomic precision for repeated operations. Finally, the atomic lock-on procedure does not need to be performed at each atomic site, and instead a live position correction can be utilized based on the ADF detector feedback, again minimizing the time per defect structure. Moreover, repeated update of the position of the focused electron beam with respect to the atomic lattice and specifically to the exact positions of manipulated atoms allows maintenance of exact lattice information, which, in turn, allows for repeated and atomically precise movements over large material areas. These experiments combined demonstrate the atomic steering with the van der Waals layered magnetic semiconductor CrSBr, and it is expected that similar steering strategies to be integrable for other material systems with alterations of the scan type and dose distribution. The experiments demonstrate the steering of entire atomic columns of Cr atoms into interstitial sites in neighboring atomic columns. The approach may be conducted repeatedly over large areas by moving from atomic site to atomic site performing for example pre-defined scans or adaptive scanning by dynamically updating scan strategies during execution of the procedure. Further, although the above disclosure describes the method in conjunction with a multi-layer crystalline material, this method is applicable to atomically thin layers, such as single layer materials. FIG. 18 shows the electron beam targeting an atom at an initial location 12 in an atomic thin material 10 at a first position 11. In this figure, the target atom is ejected from the material (see 64), creating a vacancy in the material. FIG. 19 shows another configuration where the target atom at an initial location 12 is displaced from the first position 11 to another location 14 in the material 10 or to the supporting material. The steered atom can remain strongly bonded to the material from which it was ejected. Such defects can act as single optically active spin qubits, of high relevance for scalable quantum computing technologies. As was described above with respect to atomic columns, the displacement of a single atom can be monitored with high time resolution (sub-millisecond) in a scanning transmission electron microscope by positioning the focused electron beam on a single atomic site while reading out a detector signal that reflects the atomic configuration. Additional procedures were conducted using an atomically thin layer of material, WS2. The electron beam may be directed at either a single tungsten (W) site or a two sulfur (2S) atom site. In FIG. 20, the electron beam 70 is directed at a single W atom 71. The top graph shows the elastically scattered electrons on a high angle ADF (HAADF) detector. In this graph, a step-like intensity decrease 72 from the level associated with the single W atom is seen, indicating the displacement of this atom. The lower two graphs are from the HAADF-STEM images collected before the experiment was conducted, and again after the 1s targeted experiment was conducted on this W atom. Note that the W atom moved from position 73 in the left graph to position 74 in the right graph. In FIG. 21, the electron beam 70 is directed at a 2S atom site. The top graph shows the elastically scattered electrons on a high angle ADF (HAADF) detector. In this graph, a step-like intensity decrease 72 from the level associated with the displacement of a single S atom is seen, indicating the displacement of a first S atom. A second step-like intensity decrease 75 shows the displacement of the second S atom. The lower two graphs are from the HAADF-STEM images collected before the experiment was conducted, and again after the 1s targeted experiment was conducted on this 2S atom site. Note that the 2S atoms at the targeted position 76 in the left graph are removed at position 77 in the right graph visible from the reduced in atom column brightness and the crystal distortion. The fast time resolution shown in FIG. 22 also reveals intricate single atom dynamics with one single S atom moving between the targeted position and a nearby W atom site, demonstrating the ability to steer atoms within an atomically thin layer. In this specific case, the S atom is jumping between the target site 82 and a nearby W atom site 84, remaining in a partially bonded situation. The right graph shows the displaced 2S atoms at the target site 83. The procedure disclosed herein is generally applicable in any aberration corrected scanning transmission electron microscope capable of a sufficiently small electron beam and sufficiently high stability. Depending on the material, different electron acceleration energies may be required to induce a deliberate atom movement or displacement. The ability to create envisioned atomic defects and arrange them in patterns is highly sought after for scaling quantum computing applications, particularly for photonic quantum computing that relies on color centers as spin qubits. This approach enables the ability to tune the interactions between generated defects when positioned closely with atomic precision. Moreover, the atomic nature enables high density arrangement of defects. The general ability to structurally change materials enables next generation material design with applications for energy, catalysis, or high-density memory design. The present system has many advantages. These include: ^ Degree of freedom to deterministically “steer” atoms in different crystallographic directions and to well-defined positions ^ Repeated execution at atomically defined locations over large areas (keeping locked onto atomic lattice) ^ Ability to monitor the progress of the atomic motion, terminate irradiation when movement has occurred, move the atom to a new location or move it back to correct errors ^ Atom number-conserving manipulation process (atoms are not displaced out of the crystal, but are moved from their original site to a different location) ^ Applicable to numerous types of material, in particular materials that are multiple atoms in thickness. Using such thicker crystals enables defects to be produced deep within the crystal which are not as sensitive to deleterious effects from the surface such as surface contamination and other surface chemistry. The present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, other various embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Further, although the present disclosure has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the present disclosure as described herein.

Claims

What is claimed is:

1. A method of moving an atom in a material from a first position to a predetermined second position, comprising: using a scanning transmission electron microscope (STEM) to direct an electron beam at the first position; and repeatedly moving the electron beam in a predetermined pattern to displace the atom from the first position and guide it toward the second position within the material.

2. The method of claim 1, wherein the predetermined pattern comprises a 1 dimensional (1D) scan.

3. The method of claim 1, wherein the predetermined pattern comprises a two dimensional (2D) scan.

4. The method of claim 3, wherein the 2D scan comprises an ellipsoid or an ellipsoid spiral.

5. The method of claim 1, further comprises adjusting an intensity of the electron beam as it moves in the predetermined pattern.

6. The method of claim 5, wherein the intensity is greater near the first position and the second position.

7. The method of claim 1, further comprising using a detector to measure a signal sensitive to an atomic structure of the material.

8. The method of claim 7, further comprising using the signal to identify that the atom has been moved to the second position.

9. The method of claim 7, further comprising using the signal to detect errors in atom movement.

10. The method of claim 7, wherein the detector comprises an annular dark field (ADF) detector, an annular brightfield (ABF) detector, a bright field (BF) detector, a secondary electron (SE) detector, or photon detectors or charge transport signals.

11. The method of claim 1, wherein the material has a crystalline structure.

12. The method of claim 11, wherein the material is a single monolayer in thickness.

13. The method of claim 11, wherein the material is up to 100 atoms thick.

14. A method of moving one or more first atoms arranged in a first column, each moving from a first position to a second position within a material, and moving one or more second atoms arranged in a second column, each moving from a third position to a fourth position within a material, the method comprising: using a scanning transmission electron microscope (STEM) to direct an electron beam to the first position; repeatedly moving the electron beam in a first predetermined pattern to displace the one or more first atoms from the first position and guide them toward the second position; terminating movement of the electron beam in the first predetermined pattern when the one or more first atoms are at the second position within the material; using the STEM to direct the electron beam to the one or more second atoms arranged in the second column at the third position; repeatedly moving the electron beam in a second predetermined pattern to displace the one or more secondatoms from the third position and guide them toward the fourth position; and terminating movement of the electron beam in the second predetermined pattern when the one or more second atoms are at the fourth position within the material.

15. The method of claim 14, further comprising using a detector to measure a signal sensitive to an atomic structure of the material.

16. The method of claim 15, further comprising using the signal to terminate movement of the electron beam in the first predetermined pattern and the second predetermined pattern.

17. The method of claim 15, further comprising using the signal to detect errors in atom movement.

18. The method of claim 15, wherein the detector comprises an annular dark field (ADF) detector, an annular bright field (ABF) detector, a bright field (BF) detector, a secondary electron (SE) detector, or photon detectors or charge transport signals.

19. The method of claim 14, further comprising: performing a precision location determination after the one or more first atoms have moved to the second position and before directing the electron beam toward the one or more second atoms.

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