Diamond gallium-vacancy quantum color center, application and preparation method

Abstract

This application discloses diamond gallium-vacancy quantum color center, application and preparation method. In this technical solution, a diamond gallium-vacancy quantum color center is designed, which can maintain the ground state triplet state at room temperature, and the excited state can also maintain the triplet state, and can be quantum coherently controlled; the zero phonon line is within 637nm, within the visible light range, and is easy to identify fluorescence; the quantum color center can maintain a relatively stable charge state; further, based on quantum control technology, the gallium-vacancy quantum color center can be applied to quantum sensing, quantum communication, quantum computing and other fields.

Description

Technical Field

[0001] The present application relates to the technical field of quantum information technology, and in particular to diamond gallium-vacancy quantum color centers, applications, and preparation methods. Background Art

[0002] Diamond is a wide bandgap material with ultra-high hardness, high thermal conductivity and high chemical stability. Therefore, diamond materials containing quantum color centers can be used in complex and harsh environments.

[0003] Diamond quantum color centers, represented by nitrogen-vacancy color centers, are a type of quantum spin system with a triplet ground state. Diamond nitrogen-vacancy color centers have a coherence time of milliseconds at room temperature, are easily coherently controlled by lasers, and can be applied to quantum information fields such as quantum sensing, quantum computing, and quantum communication. Diamond quantum color centers are atomic-scale in size, so diamond quantum color centers can be applied to the field of microscopic quantum information, such as quantum sensing technology at the micro-nano scale, and can be applied to biological, chemical, and physical research.

[0004] Diamond nitrogen-vacancy color centers still contain many defects that affect their coherence properties, and their coherence time needs to be further improved. Their fluorescence intensity is also weak. Nitrogen-vacancy color centers also have the disadvantage of unstable charge, which means that nitrogen-vacancy color centers will produce fluorescence flickering and cannot be further stably controlled by quantum. Researchers have been looking for other color centers to enrich the research on diamond quantum color centers. Other common diamond quantum color centers include silicon-vacancy color centers, phosphorus-vacancy color centers, and germanium-vacancy color centers. The design standards for diamond quantum color centers are based on the standards proposed by Professor DAVID AWSCHALOM of the University of California [Weber JR, Koehl WF, Varley JB, et al. Quantum computing with defects. Proceedings of the National Academy of Sciences, 2010, 107(19): 8513-8518]. The main standards include: the laser wavelength from the ground state to the excited state must be within a reasonable range (a suitable laser can be found), the color center defect state must be able to withstand temperature fluctuations (i.e., to ensure that the ground state triplet is maintained at room temperature), etc.

[0005] The main methods for preparing diamond quantum color centers are vapor deposition (CVD) and ion implantation. Diamond materials prepared by CVD have fewer defects and less quantum noise; the quantum color centers prepared by ion implantation have the advantage of high controllability of the color center position, but the disadvantage is that they contain more defects and poor crystal quality. Summary of the invention

[0006] In view of this, the present application provides diamond gallium-vacancy quantum color centers, applications and preparation methods, which can be widely used in the field of quantum information.

[0007] In a first aspect, the present application provides a diamond gallium-vacancy quantum color center, a diamond quantum color center structure formed with Be atoms as the color center vacancy.

[0008] Suitably but not restrictively, the diamond quantum color center structure further includes N and / or P atoms as doping defect atoms.

[0009] Suitably, but not limiting of the above, the doping defect atom is greater than 7 angstroms away from the gallium-vacancy color center.

[0010] In a second aspect, the present application provides an application of the diamond gallium-vacancy quantum color center as described above, and its application in visible light fluorescence recognition.

[0011] Suitably but not limitingly, the wavelength of visible light is around 673 nm.

[0012] In a third aspect, the present application provides an application of the diamond gallium-vacancy quantum color center as described above, and its application in quantum materials.

[0013] In a fourth aspect, the present application provides a method for preparing the diamond gallium-vacancy quantum color center as described above, comprising the following steps:

[0014] S1, CVD grows layer by layer to form diamond;

[0015] S2, doping Ga atoms during CVD process;

[0016] S3, performing post-processing including annealing on the diamond obtained in S2;

[0017] S4, making the diamond passing through the rear part form a diamond quantum color center structure.

[0018] Suitable but not limiting, between S2 and S3, the substrate used for CVD deposition is also peeled off.

[0019] Suitably but not limitingly, the ablation method is laser ablation.

[0020] Suitable but not limiting, the post-treatment also includes surface treatment after annealing.

[0021] The above provides diamond gallium-vacancy quantum color centers, applications and preparation methods, and designs a diamond gallium-vacancy quantum color center, which can maintain a ground state triplet state at room temperature, and an excited state can also maintain a triplet state, and can be quantum coherently controlled; the zero phonon line is within 637nm, within the visible light range, and is easy to identify fluorescence; the quantum color center can maintain a relatively stable charge state; further, based on quantum control technology, the gallium-vacancy quantum color center can be applied to quantum sensing, quantum communication, quantum computing and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0023] Figure 1 A microscopic structure diagram of a gallium-vacancy quantum color center provided in an embodiment of the present application.

[0024] Figure 2 Another microscopic structure diagram of the gallium-vacancy quantum color center provided in the embodiment of the present application.

[0025] Figure 3 Energy level diagram of the gallium-vacancy quantum color center provided in the embodiments of the present application.

[0026] Figure 4 The ground state spin electron density diagram of the gallium-vacancy quantum color center provided in the embodiments of the present application.

[0027] Figure 5 The formation energy diagram of the gallium-vacancy structure in different charge states provided in the embodiments of the present application.

[0028] Figure 6 This is a flow chart of a method for preparing a gallium-vacancy quantum color center provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0030] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0031] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0033] like Figure 1 The microstructure of the gallium-vacancy quantum color center is shown in Figure 2. Figure 1 .

[0034] like Figure 1 As shown, the largest "sphere" in the middle is the gallium atom, and the remaining "spheres" are carbon atoms.

[0035] like Figure 1 As shown, gallium-vacancy means that in diamond, a gallium atom replaces a carbon atom A and removes a carbon atom B adjacent to the gallium atom to become a "vacancy". After relaxation, the gallium atom moves between the carbon atom A and the "vacancy", forming a gallium-vacancy structure.

[0036] like Figure 2 The microstructure of the gallium-vacancy quantum color center is shown in Figure 2. Figure 2 .

[0037] like Figure 2As shown, near the gallium-vacancy color center, nitrogen atoms or phosphorus atoms are substitutionally doped. The nitrogen atoms or phosphorus atoms are more than 7 angstroms away from the gallium-vacancy color center.

[0038] like Figure 3 As shown, it is the energy level diagram of the gallium-vacancy quantum color center, which is obtained by first-principles calculation using the HSE06 hybrid functional. The energy level diagram refers to the position of the valence electron energy level of the gallium-vacancy quantum color center.

[0039] like Figure 3 As shown in the figure, the valence electron energy levels of the gallium-vacancy quantum color center are a1(1), a2(2), e x 、e y 、a1(1)'、a2(2)'、e x '、e y '. Among them, a1(1), a2(2), e x 、e y is the occupied state of the up spin, a1(1)' and a2(2)' are the occupied states of the down spin, and e x '、e y ' is an unoccupied state of the down spin.

[0040] like Figure 3 As shown, the ground state of the gallium-vacancy quantum color center is a triplet state, and the electrons in the triplet state come from e x 、e y , which satisfies the basic conditions of a quantum color center.

[0041] like Figure 3 As shown, the gallium-vacancy quantum color center e x With e x The energy level difference of ' is about 1.67eV, e y With e y The energy level difference of ' is about 1.67eV, which is large enough to allow the quantum color center to exist stably at room temperature. x or y The electron on the e will not spontaneously jump to x 'or e y ', able to maintain the ground state spin triplet state.

[0042] like Figure 4 As shown, it is the ground state spin electron density diagram of the gallium-vacancy quantum color center. This diagram is obtained by first-principles calculation using the HSE06 hybrid functional. The electron density refers to the electron cloud obtained by subtracting the lower spin charge density from the upper spin charge density. The electron cloud is mainly concentrated near the gallium-vacancy quantum color center.

[0043] like Figure 5The following is the formation energy diagram of the gallium-vacancy (Ga-Vacancy, referred to as GaV) structure in different charge states. 0 , GaV 1 , GaV -1 , GaV -2 , GaV 2 They represent the 0, 1, -1, -2 and 2 charge states of GaV. This figure is obtained by first-principles calculations using the HSE06 hybrid functional. The formation energy is based on GaV 0 The formation energy of GaV 0 The formation energy is 0eV. Gallium-vacancy quantum color center refers specifically to GaV -1 , that is, when GaV is in the -1 valence state. In order for the gallium-vacancy quantum color center to maintain the -1 charge state, the Fermi level needs to be raised to the range of 1.8 to 3.6 eV.

[0044] like Figure 2 and Figure 5 As shown, the valence electrons of phosphorus or nitrogen atoms are 5, which can increase the Fermi level and can act as electron donors to supply GaV, causing GaV to be in a -1 valence state and forming a gallium-vacancy quantum color center; and phosphorus or nitrogen atoms can make the charge state of the gallium-vacancy quantum color center more stable.

[0045] According to first-principles calculations, the gallium-vacancy quantum color center zero phonon line is around 673nm, which is within the visible light wavelength range that can be observed by the human eye.

[0046] When the gallium-vacancy quantum color center is in the ground triplet state, when light shines on the gallium-vacancy quantum color center, an electron on a1(1)' or a2(2)' will be excited to e x 'or e y ' orbit, making the excited state also a triplet state. When the gallium-vacancy quantum color center is in the excited triplet state, when e x 'or e y When an electron in the orbit falls back to a1(1)' or a2(2)', the gallium-vacancy quantum color center will observe fluorescence. Raman spectroscopy tests have shown that the zero phonon line of the gallium-vacancy color center is around 673nm.

[0047] like Figure 5 Shown are the steps for preparing diamond gallium-vacancy quantum color centers.

[0048] Step 1: Prepare the substrate and place it in the CVD equipment on the sample stage of the CVD equipment.

[0049] Step 2: Introduce methane, hydrogen, gallium source gas, nitrogen or phosphine to start CVD growth of diamond.

[0050] Step 3: growing diamond layer by layer. The gallium source gas mainly provides gallium atoms for the gallium-vacancy quantum color center. During the diamond CVD layer-by-layer growth process, the gallium atom is doped into the diamond to replace a carbon atom.

[0051] Step 4: After growth, the diamond is peeled off from the substrate, preferably by laser peeling.

[0052] Step 5: Perform post-processing operations such as annealing and surface treatment on the diamond. Annealing is mainly to gradually migrate the atomic vacancies in the diamond to the vicinity of the gallium atoms to form a gallium-vacancy structure.

[0053] The nitrogen or phosphine is mainly doped into the diamond to form a nitrogen-doped or phosphorus-doped structure, which provides an electron for the gallium-vacancy structure, making the charge state of the gallium-vacancy quantum color center more stable. The diamond containing the gallium-vacancy color center can be used in quantum sensing, quantum communication, quantum computing and other fields.

[0054] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A diamond gallium-vacancy quantum color center, characterized in that: A diamond quantum color center structure formed with Ga atoms as color center vacancies; the diamond quantum color center structure also includes N and / or P atoms as doping defect atoms, the valence electrons of phosphorus atoms or nitrogen atoms are 5, which can increase the Fermi level and can serve as electron donors to supply GaV, so that GaV is in a -1 valence state, forming a gallium-vacancy quantum color center, the doping defect atoms are greater than 7 angstroms away from the gallium-vacancy color center; the gallium-vacancy quantum color center can maintain a ground state triplet at room temperature, and the excited state can also maintain a triplet state, and can be quantum coherently controlled, with a zero phonon line at 637nm.

2. An application of the diamond gallium-vacancy quantum color center as claimed in claim 1, characterized in that: Its application in visible light fluorescence recognition.

3. The application according to claim 2, characterized in that: The wavelength of visible light is around 673nm.

4. An application of the diamond gallium-vacancy quantum color center as claimed in claim 1, characterized in that: Its applications in quantum materials.

5. A method for preparing a diamond gallium-vacancy quantum color center as claimed in claim 1, characterized in that: The following steps are involved: S1, CVD grows diamond layer by layer; S2, doping Ga atoms during CVD process; S3, performing post-processing including annealing on the diamond obtained in S2; S4, making the diamond passing through the rear part form a diamond quantum color center structure.

6. The preparation method according to claim 5, characterized in that: Between S2 and S3, the substrate used for CVD deposition is also stripped.

7. The preparation method according to claim 6, characterized in that: The stripping method is laser stripping.

8. The preparation method according to claim 5, characterized in that: The post-treatment also includes surface treatment after annealing.

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