Scanning probe measuring device for imaging needle point by needle point and control method

Abstract

The invention relates to the technical field of scanning tunneling microscopes, and discloses a scanning probe measuring device and a control method for pinpoint-to-pinpoint imaging, two pinpoints are oppositely arranged, and the pinpoints are accurately controlled and movably positioned based on a basic working mode of a scanning probe microscope. A needle tip-tunnel junction-needle tip working structure is established, after bias voltage is applied externally, electron tunneling between needle tips only relates to a small number of atoms or single atoms at the tail ends of the needle tips, the tunneling effect that the small number of atoms contribute to electrons is achieved, and therefore small number or single atom imaging is achieved. The device can be rapidly transplanted to application scenes of low temperature, strong magnetic field, optical measurement and the like, the double-needle-point structure is regulated and controlled through piezoelectric displacement or an electric field, tunnel junction width and barrier height can be optimized in real time, and research on dynamic construction and dynamic electrical characteristics of nanoscale tunnel junctions is greatly facilitated.

Description

Technical Field

[0001] This invention relates to the field of scanning tunneling microscopy, and more specifically to a scanning probe measurement device and control method for tip-to-tip imaging. Background Technology

[0002] Since its invention by Binnig and Rohrer in 1981, the Scanning Tunneling Microscope (STM) has revolutionized research paradigms in surface science, materials physics, and nanotechnology due to its atomic-level spatial resolution. Its core principle is based on the tunneling effect in quantum mechanics: when the distance between a metal tip and the surface of a conductive sample is reduced to the nanometer scale, electrons can tunnel through the energy barrier under an applied bias voltage, forming a tunneling current. Using a piezoelectric ceramic-driven three-dimensional nanopositioning system, the tip can scan the sample surface with atomic precision. The real-time feedback of tunneling current changes, after algorithmic processing, can reconstruct the surface morphology and local density of states (LDOS) distribution (Binnig et al., Physical Review Letters, 1982). However, this classic technical framework has inherent limitations in its physical mechanisms and engineering implementation, severely restricting the realization of its ultimate resolution capabilities.

[0003] The core contradiction of traditional scanning tunneling microscopy (STM) stems from the scale mismatch between the nanoscale tip and the macroscopic sample surface. Although the tip is finely machined (with a radius of curvature of about 5-50 nanometers, equivalent to a micro-protrusion composed of dozens of atoms), its detection range covers a region of the sample surface far exceeding the atomic scale (typically on the order of square micrometers). This "nanoprobe-macroscopic field of view" physical characteristic means that when the tip approaches the sample, dozens of sample atoms within a range of about 1-3 nanometers below it simultaneously participate in the tunneling process (Chen, CJ, Introduction to Scanning Tunneling Microscopy, 1993).

[0004] Specifically, even if the tip is a signal collector with a single atom at its tip, it still forms parallel electron channels with multiple atoms in the corresponding region of the sample surface below it. For example, when imaging a metal surface, multiple adjacent atoms on the sample surface may simultaneously cover the area below the tip. The electron clouds of these atoms collectively emit tunneling electrons towards the tip, resulting in the measurement signal being essentially the overall average of contributions from multiple atoms (Tersoff et al., Phys. Rev. Lett, 1985). More seriously, due to the periodicity of the atomic arrangement on the sample surface, the tip periodically triggers cooperative responses from different atomic groups during scanning, causing "superlattice fringes" that are not present in the image (Hofer et al., Science, 2003). This signal aliasing caused by the nonlocality of the detection region has become a core obstacle limiting STM from achieving true single-atom resolution.

[0005] Existing attempts generally focus on two aspects: tip fabrication and system architecture. Regarding tip optimization, Field Ion Microscopy (FIM) technology can fabricate ideal tips containing only a single atom at the tip through field evaporation (Nakamura et al., Ultramicroscopy, 2012). However, such tips are highly susceptible to damage in practical operation due to mechanical vibration, thermal drift, or accidental contact. Relying on ultra-high vacuum interconnect systems, they only offer improvement in single-atom imaging because they still depend on the traditional tip-sample configuration, failing to avoid multi-atom interactions between tip atoms and the sample region. In terms of system architecture modification, the STM-BJ method establishes contact through mechanical impact between the tip and the sample, pulling the tip to form a metallic atomic line, creating a conductive channel between the tip and the sample. This allows for direct measurement of quantum conductivity at the single-atom scale, but it does not reflect the real-space atomic positions and is currently not applicable to imaging. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a scanning probe measurement device and control method for tip-to-tip imaging. It proposes a tip-tunnel junction-tip structure, achieving precise tunnel junction construction and high repeatability through dynamic feedback control of the dual-tip spacing and atomic-level precision adjustment. Technically, this design combines high controllability, high-efficiency construction, and universal scalability. The fabrication and control methods are simple, and a wide range of tip materials can be selected. This detection method and experimental platform for single-atom imaging will be beneficial for research on single-atom interactions, exploration of physical properties under extreme conditions, and the study of quantum transport phenomena.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: In a first aspect, the present invention provides a scanning probe measurement device for tip-to-tip imaging, comprising: a frame, a coarse approximation motor, an XYZ three-dimensional scanner, and a first probe; The coarse approximation motor is fixed to the frame, one end of the XYZ 3D scanner is fixed to the free end of the coarse approximation motor and is coaxial with the driving direction of the coarse approximation motor, and the first probe is fixed to the free end of the XYZ scanner, forming a structure in which the coarse approximation motor pushes the first probe forward. The feature is that it further includes a second probe; the second probe is fixed on the frame at the other end away from the coarse approximation motor, and its tip can be aligned with the tip of the first probe.

[0008] In one embodiment, the XYZ three-dimensional scanner and the coarse approximation motor are integrated to form a drive and scanning unit, which is mounted on the frame. It can drive the first probe to move in a spatial range and perform scanning actions in the plane, so that the distance between the tip of the second probe and the tip of the first probe is small enough to allow the tunneling effect to occur. By applying a bias voltage, a tip-tunnel junction-tip structure is formed, and the geometric parameters and barrier characteristics of the tunnel junction can be adjusted in real time. It can also maintain the dynamic stability of the tunneling effect through feedback control.

[0009] In one embodiment, the first probe, the second probe, and the coarse approximation motor drive direction are coaxially arranged; when the frame is a tubular frame, the tubular frame, the first probe, the second probe, and the coarse approximation motor drive direction are all coaxially arranged.

[0010] In one embodiment, it further includes a second probe holder and a clamping spring sheet; the frame is provided with a slot and an opening; the second probe holder is placed in the slot; the clamping spring sheet is placed between the second probe holder and the slot wall to clamp the second probe holder; the non-needle tip of the second probe is fixedly connected to the second probe holder and extends out of the slot through the opening.

[0011] In one embodiment, an electrode interface is also included, which is used for signal input and signal readout, to transmit the drive signal of the external controller to the drive and scanning unit, to transmit the bias voltage to the tip-tunnel junction-tip structure, and to transmit the corresponding tunneling current to the acquisition device.

[0012] In one embodiment, the frame is made of one or more of titanium, tantalum, sapphire, and zirconium oxide; the second probe and the first probe are made of one or more of tungsten, gold, silver, and platinum-iridium alloy, or one or more of silicon, germanium, and gallium arsenide, or a material modified with CO single molecules, or a nanoscale thin film grown on any needle-shaped substrate. The tips of the second probe and the first probe may be modified with carbon nanotubes, or carbon nanotubes may be used directly as needle tips.

[0013] Secondly, the present invention provides a control method for a scanning probe measurement device for tip-to-tip imaging, specifically including: Under an optical microscope, the second probe holder is moved so that the second probe and the first probe coincide in the vertical direction, and the distance between the tips of the two probes is controlled within a set value. A drive signal is output to the drive and scanning unit through the electrode interface, so that the first probe moves along the axis of the second frame and approaches the distance between it and the second probe in the longitudinal direction. Using an optical microscope for observation, the position of the tip of the first probe in the plane is adjusted by the drive signal. When the distance between the tips of the two probes is close, a scanning signal is output to make the first probe perform a scanning action. If no tunneling current signal is obtained, the drive signal makes the first probe move forward one step along the axis or adjust its position in the plane. If a tunneling current signal is obtained, the tunnel junction construction process stops.

[0014] In one embodiment, the tip deflection of the first probe is controlled by dynamically adjusting the drive signal output, or the distance and relative configuration between the tips of the two probes are adjusted to keep the second probe and the first probe within the distance where the tunneling effect can occur.

[0015] In one embodiment, the process of acquiring the tunneling current-distance tunneling spectrum is further included, specifically: opening the tunnel junction feedback loop, adjusting and stabilizing the distance between the tips of the second probe and the first probe at the required size by setting the bias voltage and the magnitude of the target tunneling current; closing the feedback loop, and linearly changing the distance between the tips of the two probes by controlling the drive and scanning unit under a determined bias voltage, while detecting the change in tunneling current, so as to obtain the tunneling current-distance tunneling spectrum of the tunneling current changing with the distance between the tips of the two probes after the tips of the two probes are aligned.

[0016] In one embodiment, the process of obtaining the tunneling current-bias voltage tunneling spectrum is further included, specifically: opening the tunnel junction feedback loop, adjusting the spacing between the tips of the second probe and the first probe to a set position by setting the initial tunneling current and the initial bias voltage; closing the tunnel junction feedback loop, and under the determined spacing between the tips of the second probe and the first probe, detecting the change in tunneling current while changing the bias voltage of the tunnel junction by the external controller, so as to obtain the tunneling current-bias voltage tunneling spectrum after the tips of the two probes are aligned.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are: (1) The second probe holder is fixed by a clamping spring sheet, which provides elasticity for long-range action and can work safely in ambient temperature and low temperature environments. The position of the needle tip can be pre-adjusted, making operation convenient.

[0018] (2) The frame structure is reasonably designed, maintaining high rigidity while having a small overall size. It can work in a narrow low-temperature strong magnetic field space, and can also be transplanted to any optical table. It is easy to reserve functional expansion interfaces and can be placed in micro-nano processing cavities.

[0019] (3) A scanning probe measurement device for tip-to-tip imaging according to the present invention: Based on the working principle of quantum tunneling effect, using a driving and scanning unit, the distance between the two tips can be dynamically fed back and adjusted, so as to quickly adjust the distance between the tips to a suitable size without damaging the tips. The unit constructs the tunnel junction with atomic-level scanning precision. This process has the characteristics of high repeatability and high efficiency, and is very environmentally dependent.

[0020] (4) A scanning probe measurement device for tip-to-tip imaging according to the present invention: The controller system is no different from a basic ordinary scanning tunneling microscope. It requires a preamplifier circuit to connect to the tip to amplify the tunneling current into a voltage signal, which is then acquired by the controller. At the software level, it is only necessary to monitor the tunneling current signal and instruct the drive and scanning unit to react in a timely manner. It can directly use readily available commercial controller equipment.

[0021] (5) A scanning probe measurement device for tip-to-tip imaging according to the present invention: The overall structure is simple and can realize the purpose of a few atoms participating in the tunneling electrons to obtain the tunneling current, thereby realizing a few or single-atom imaging. By changing the tip, the distance between the tunnel junction and the bias voltage, it can be applied to a variety of studies and has guiding significance for people to deeply understand the underlying theory of nanoelectronic devices. Attached Figure Description

[0022] Figure 1 This is a basic structural view of the scanning probe measuring device for tip-to-tip imaging according to the present invention; Figure 2Aand Figure 2B This is an external view of a scanning probe measuring device for tip-to-tip imaging according to Embodiment 1 of the present invention; Figure 3A and Figure 3B This is an internal view of a scanning probe measuring device for tip-to-tip imaging according to Embodiment 1 of the present invention; Figure 4 This is a flowchart illustrating the operation of a scanning probe measurement device for tip-to-tip imaging according to Embodiment 1 of the present invention. Figure 5 This is a simplified illustrative view of a scanning probe measuring device for tip-to-tip imaging according to Embodiment 2 of the present invention; Figure 6 This is an overall view of a needle-to-needle imaging scanning probe measurement device according to Embodiment 3 of the present invention.

[0023] In the figure: 1. Frame; 2. Second probe holder; 3. Clamping spring sheet; 4. Second probe; 5. First probe; 6. Coarse approximation motor; 7. Electrode interface; 8. Drive and scanning unit; 9. XYZ 3D scanner. Detailed Implementation

[0024] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] Solutions derived by those skilled in the art through equivalent substitution and conventional reasoning of the technical features of the present invention without creative effort all fall within the protection scope of the present invention.

[0026] Example 1 A scanning probe measurement device for tip-to-tip imaging according to the present invention is shown in the basic structural view below. Figure 1 The system includes a frame 1, a coarse approximation motor 6, an XYZ 3D scanner 9, a first probe 5, and a second probe 4. The coarse approximation motor is fixed to the frame. One end of the XYZ 3D scanner is fixed to the free end of the coarse approximation motor and is coaxial with the driving direction of the coarse approximation motor. The first probe is fixed to the free end of the XYZ scanner, forming a structure in which the coarse approximation motor pushes the first probe forward. The XYZ 3D scanner and the coarse approximation motor can be integrated to form a drive and scanning unit, which is mounted on the frame. The second probe is mounted on the frame in a horizontally movable manner.

[0027] A scanning probe measurement device for tip-to-tip imaging according to the present invention includes an isometric oblique projection and a top view in its external view, see [reference needed]. Figure 2A and Figure 2B Its internal views include side sectional views and internal views that conceal the frame structure; see [link / reference]. Figure 3A and Figure 3BThe device includes a frame 1, a second probe holder 2, a clamping spring sheet 3, a second probe 4, a first probe 5, an electrode interface 7, and a driving and scanning unit 8. It should also include a controller driving module, a controller signal acquisition module, a preamplifier, and a host computer. The main innovation of this invention lies in the device for efficiently constructing a tunnel junction to achieve single-electron tunneling. Therefore, the controller driving module, controller signal acquisition module, preamplifier, and host computer are not shown in the accompanying drawings.

[0028] The clamping spring plate 3 is pre-fixed on the frame 1 and has a certain elasticity. Its elasticity is used to clamp the second probe holder 2. The clamping spring plate 3 can be replaced to adjust the elasticity. The drive and scanning unit 8 is fixed on the frame 1. Its drive motor can carry objects to move over a large range in space and can also perform scanning actions in a plane. The drive and scanning unit 8 can be freely replaced.

[0029] The tips of the second probe 4 and the first probe 5 are free ends, and the non-tip tips are fixed ends. The tips of the second probe 4 and the first probe 5 are arranged opposite each other and are relatively close. The two fixed ends of the tips are arranged opposite each other and are relatively far apart. The second probe 4 is connected to the second probe holder 2 through the fixed end, and the fixed end of the first probe 5 is connected to the driving and scanning unit 8.

[0030] The second probe holder 2 is pressed by elastic force, but its position relative to the frame 1 can still be adjusted to pre-adjust the positional relationship between the second probe 4 and the first probe 5. The electrode interface 7 is used for signal input and signal readout, transmitting the drive signal from the external controller to the drive and scan unit 8, transmitting a bias voltage to the tip-tunnel junction-tip structure, and transmitting the current signal of the tip-tunnel junction-tip structure to the acquisition device. The drive and scan unit 8 precisely positions and controls the displacement of the first probe 5, making the distance between the tip of the second probe 4 and the tip of the first probe 5 small enough to allow the tunneling effect to occur, thus forming a tip-tunnel junction-tip structure.

[0031] The frame 1, the second probe 4, the first probe 5, the driving and scanning unit 8, and the electrode interface 7 are all coaxially arranged.

[0032] In optional embodiments, the frame 1 is made of materials with good thermal conductivity, vacuum compatibility and immunity to magnetic fields, such as titanium, tantalum, sapphire, zirconium oxide, etc., the clamping spring sheet 3 is made of materials such as phosphor bronze, beryllium copper, etc., and the electrode interface 7 is made of materials such as sapphire, zirconium oxide, etc. with excellent insulation performance and extremely low leakage current.

[0033] In optional embodiments, the materials of the second probe 4 and the first probe 5 can be metals, such as tungsten, gold, silver, platinum-iridium alloys, or semiconductor materials such as silicon, germanium, gallium arsenide, etc., or needle tips modified with single molecules such as CO, or nanoscale thin films grown on any needle tip-shaped substrate.

[0034] In an optional embodiment, the tips of the second probe and the first probe may be modified with carbon nanotubes, or carbon nanotubes may be used directly as the needle tip.

[0035] In optional embodiments, the driving and scanning unit 8 can be a multi-zone driven inertial piezoelectric motor device, with application publication number CN103986365A; it can be a dual piezoelectric linear nano-positioning piezoelectric actuator, with application publication number CN1996737A; or it can be a scanning tip microscope body with a coarse approximation motor that can be detached from the scanning structure, with application publication number CN102866265A. The driving and scanning unit 8 can be a moving component that can push back and forth along the axial direction of the frame 1 to realize the forward and backward movement of the first probe 5 in the axial direction. The driving and scanning unit 8 can drive the first probe 5 to scan in a plane perpendicular to the second frame axis with a resolution of atomic precision.

[0036] In an optional embodiment, the driving and scanning unit 8 can be a multi-dimensional piezoelectric motor with a single piezoelectric device, the application publication number of which is CN119298715A, or an X-electrode segmented cross multi-dimensional piezoelectric motor, the application publication number of which is CN112290826A. The driving and scanning unit 8 can realize the forward and backward movement of the first probe 5 along the axial direction, and can also realize the precise displacement of the first probe 5 in a plane perpendicular to the axial direction. The driving and scanning unit 8 can drive the first probe 5 to scan in a plane perpendicular to the second frame axis with a resolution of atomic precision.

[0037] The efficient tunnel junction construction workflow of this embodiment is as follows: Figure 4As shown, the specific workflow can be as follows: First, under an optical microscope, locate the second probe 4 and the first probe 5. Move the second probe holder 2 so that the second probe 4 and the first probe 5 are substantially aligned vertically. At this point, the distance between the two probe tips in the plane should be less than 10 micrometers. Subsequently, the controller outputs a drive signal to the drive and scanning unit 8 through the electrode interface 7, causing the first probe 5 to move along the axis of the second frame, approaching the distance between it and the second probe 4 in the longitudinal direction. Using an optical microscope, the position of the first probe 5 tip in the plane can be adjusted through the drive signal. When the two probe tips are close together, a scanning signal is output to cause the first probe 5 to perform a scanning action. If no tunneling current signal is obtained, the drive signal causes the first probe 5 to move forward one step or adjust its position in the plane accordingly. If a tunneling current signal is obtained, the tunnel junction construction process stops.

[0038] In an optional embodiment, the method of maintaining the tip-tunnel junction-tip working structure may be to dynamically adjust the drive signal output through a feedback process set by software, control the tip deflection of the first probe 5, and keep the second probe 4 and the first probe 5 always within the distance where the tunneling effect can occur. Alternatively, the distance between the tips and the relative configuration between the tips may be adjusted.

[0039] Since the tunnel junction is much smaller than the mean free path of electron motion, it does not necessarily require vacuum experimental conditions. The working environment can be room temperature, atmospheric conditions, low temperature, or strong magnetic field environment.

[0040] This embodiment also provides an experimental setup applicable to a highly efficient needle-to-needle imaging scanning probe measurement device as described above: Maintaining the spacing and relative configuration between the tips, the scanning signal is output. The first probe scans in the conventional constant current mode or constant height mode of the scanning tunneling microscope, records the tunneling current signal and corresponds it to the scanning signal, and obtains a single-atom scanning imaging pattern.

[0041] The tunnel junction feedback loop is opened, and the spacing between the second probe 4 and the first probe 5 is temporarily stabilized at the required size by setting the bias voltage and the target tunneling current. Then the feedback loop is closed, and under the determined bias voltage, the spacing between the two probe tips is linearly changed by controlling the drive and scanning unit 8, while detecting the change in tunneling current, so as to obtain the tunneling current-distance tunneling spectrum, which shows the change in tunneling current with the spacing between the two probe tips after the probe tips are aligned.

[0042] A closed feedback loop is formed, and the initial tunneling current and initial bias voltage are set to stabilize the distance between the two probe tips at a certain position. Then, the feedback loop is closed, and with the determined distance between the tips of the second probe 4 and the first probe 5, the external controller changes the bias voltage on the tunnel junction while detecting the change in tunneling current to obtain the tunneling current-bias voltage tunneling spectrum after the tips of the two probes are aligned.

[0043] In a low-temperature environment, the second probe 4 and the first probe 5 are made of different materials, and the tips are fabricated using micro-nano processing techniques, including single-molecule tip modification, to finely adjust the height, shape, and width of the tunneling barrier, thereby achieving controllable regulation of quantum transport. Under a magnetic field, related experiments are repeated to analyze the electronic coherence of the quantum transport process.

[0044] Example 2 The difference between this embodiment and Embodiment 1 is that the alignment of the second probe 4 and the first probe 5 no longer relies specifically on the driving and scanning unit 8, but can be achieved through the tip manufacturing process. For example... Figure 5 A simplified view of the target structure is given.

[0045] In an optional embodiment, for a single metal wire, such as a tungsten wire, it can be placed vertically in a sodium hydroxide solution for alternating current electrochemical etching until a neck, visible to the naked eye under an optical microscope, is formed at the interface between the solution and the wire—that is, the point where the wire diameter suddenly decreases. Then, focused ion beam processing technology is used to further thin the wire diameter. The processing can be stopped when nanoscale fractures are clearly shown in the electron microscope image, or when the electron microscope image still shows a connection with minimum processing precision. In an optional embodiment, a silicon cantilever beam tip is brought close to the surface of a metal substrate to form a jump-to contact, and then slowly withdrawn, which can stretch out nanowire or atomic chain structures. A local electric field is applied to drive atomic migration, forming a smooth tunneling interface.

[0046] Example 3 like Figure 6 As shown, the difference between this embodiment and Embodiment 1 is that in this embodiment, the second probe 4 and the first probe 5 are not required to be placed along the axial direction, nor are they required to be placed coaxially. The distance between the tips of the second probe 4 and the first probe 5 is kept within the distance required by the quantum tunneling effect, and their relative configuration can be freely changed. Figure 6 An optional implementation scheme is presented.

[0047] In this embodiment, the driving and scanning unit 8 is connected to the external frame, the second probe 4 is connected to the driving and scanning unit 8 or directly connected to the external frame, and the first probe 5 is connected to the driving and scanning unit 8. The working process will not be described in detail.

[0048] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A scanning probe measurement device for tip-to-tip imaging, comprising: The frame, coarse approximation motor, XYZ 3D scanner, and first probe; The coarse approximation motor is fixed to the frame, one end of the XYZ 3D scanner is fixed to the free end of the coarse approximation motor and is coaxial with the driving direction of the coarse approximation motor, and the first probe is fixed to the free end of the XYZ scanner, forming a structure in which the coarse approximation motor pushes the first probe forward. The feature is that it further includes a second probe; the second probe is fixed on the frame at the other end away from the coarse approximation motor, and its tip can be aligned with the tip of the first probe.

2. The scanning probe measuring device for tip-to-tip imaging according to claim 1, characterized in that, The XYZ three-dimensional scanner and the coarse approximation motor are integrated into a drive and scanning unit, which is mounted on the frame. It can drive the first probe to move in a spatial range and perform scanning actions in the plane, so that the distance between the tip of the second probe and the tip of the first probe is small enough to allow the tunneling effect to occur. By applying a bias voltage, a tip-tunnel junction-tip structure is formed, and the geometric parameters and barrier characteristics of the tunnel junction can be adjusted in real time. It can also maintain the dynamic stability of the tunneling effect through feedback control.

3. The scanning probe measuring device for tip-to-tip imaging according to claim 1, characterized in that, The first probe, the second probe, and the coarse approximation motor are coaxially arranged; when the frame is a tubular frame, the tubular frame, the first probe, the second probe, and the coarse approximation motor are all coaxially arranged.

4. The scanning probe measuring device for tip-to-tip imaging according to claim 1, characterized in that, It also includes a second probe holder and a clamping spring sheet; the frame is provided with a slot and an opening; the second probe holder is placed in the slot; the clamping spring sheet is placed between the second probe holder and the slot wall to clamp the second probe holder; the non-needle tip of the second probe is fixedly connected to the second probe holder and extends out of the slot through the opening.

5. The scanning probe measuring device for tip-to-tip imaging according to claim 1, characterized in that, It also includes an electrode interface, which is used for signal input and signal readout, to transmit the drive signal of the external controller to the drive and scanning unit, to transmit the bias voltage to the tip-tunnel junction-tip structure, and to transmit the corresponding tunneling current to the acquisition device.

6. The scanning probe measuring device for tip-to-tip imaging according to claim 1, characterized in that, The frame is made of one or more of titanium, tantalum, sapphire, and zirconium oxide; the second probe and the first probe are made of one or more of tungsten, gold, silver, and platinum-iridium alloy, or one or more of silicon, germanium, and gallium arsenide, or materials modified with CO single molecules, or nanoscale thin films grown on any needle-shaped substrate. The tips of the second probe and the first probe are modified with carbon nanotubes, or carbon nanotubes are used directly as needle tips.

7. A control method for a scanning probe measuring device for tip-to-tip imaging as described in any one of claims 1 to 6, specifically comprising: Under an optical microscope, the second probe holder is moved so that the second probe and the first probe coincide in the vertical direction, and the distance between the tips of the two probes is controlled within a set value. A drive signal is output to the drive and scanning unit through the electrode interface, so that the first probe moves along the axis of the second frame and approaches the distance between it and the second probe in the longitudinal direction. Using an optical microscope for observation, the position of the tip of the first probe in the plane is adjusted by the drive signal. When the distance between the tips of the two probes is close, a scanning signal is output to make the first probe perform a scanning action. If no tunneling current signal is obtained, the drive signal makes the first probe move forward one step along the axis or adjust its position in the plane. If a tunneling current signal is obtained, the tunnel junction construction process stops.

8. The control method of the scanning probe measuring device for tip-to-tip imaging according to claim 7, characterized in that, By dynamically adjusting the drive signal output, the tip deflection of the first probe can be controlled, or the distance and relative configuration between the tips of the two probes can be adjusted to keep the second probe and the first probe within the distance where the tunneling effect can occur.

9. The control method of the scanning probe measuring device for tip-to-tip imaging according to claim 7, characterized in that, It also includes the process of acquiring the tunneling current-distance tunneling spectrum, specifically including: opening the tunnel junction feedback loop, adjusting and stabilizing the distance between the tips of the second probe and the first probe at the required size by setting the bias voltage and the target tunneling current; closing the feedback loop, and linearly changing the distance between the tips of the two probes by controlling the drive and scanning unit under a determined bias voltage, while detecting the change in tunneling current, so as to obtain the tunneling current-distance tunneling spectrum of the tunneling current changing with the distance between the tips of the two probes after the tips of the two probes are aligned.

10. The control method of the scanning probe measuring device for tip-to-tip imaging according to claim 7, characterized in that, It also includes the process of obtaining the tunneling current-bias voltage tunneling spectrum, specifically including: opening the tunnel junction feedback loop, adjusting the spacing between the tips of the second probe and the first probe to stabilize at the set position by setting the initial tunneling current and the initial bias voltage; closing the tunnel junction feedback loop, and under the determined spacing between the tips of the second probe and the first probe, the external controller changes the bias voltage of the tunnel junction while detecting the change in tunneling current, so as to obtain the tunneling current-bias voltage tunneling spectrum after the tips of the two probes are aligned.

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