超硬材料BC_2N的一种新亚稳结构及其高压物性预测
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摘要
硼(B)、碳(C)、氮(N)轻元素因具有较小的原子半径和极强的相互键合能力,其形成的化合物极易形成强共价键和高原子密度的三维网状致密结构,从而成为寻找制备超硬材料的备选体系.本文基于最新研究的机械性能优异的体心四方碳结构模型,构造了一种具有四方对称结构、空间群为I4/mmm的BC2N潜在超硬化合物新结构.利用基于密度泛函理论的第一性原理计算方法,系统地研究了该化合物四方相新结构的热力学、力学和动力学稳定性,表明该四方相BC2N至少在0–60 GPa的压力范围内是力学和动力学稳定的;热力学计算结果显示该结构结合能稍高于BC2N化合物中最稳定的纤锌矿结构,表明新构造的四方结构是BC2N化合物的一个亚稳结构,且其不可压缩性大于其他的硼-碳-氮类化合物如B2CN, BC4N等.在结构稳定性研究的基础上,本文计算了该四方相BC2N化合物在0–60 GPa压力范围内的电子结构,发现其在零压下具有2.16 eV的带宽,为半导体,且随着压力的增加,带隙逐渐加宽;高压弹性特性研究表明BC2N化合物四方结构的体弹性模量、剪切模量、杨氏模量、泊松比、德拜温度、最小热导率和弹性波速均随压力增加呈现出不同的增加趋势且属脆性体质,其弹性各向异性在高压下变得更加明显;同时,大的体弹性模量、大的剪切模量及高维氏硬度表明所构造的空间群为I4/mmm的四方结构是BC2N化合物的一种潜在超硬新结构.
Light elements boron(B), carbon(C) and nitrogen(N) have small atomic radius and strong bonding ability, and the formed compounds are easy to form strong covalent bonds and high atomic density three-dimensional networks structures, makes it an alternative system for the preparation of superhard materials. Based on the newly studied bodycentered tetragonal carbon structure model with excellent mechanical properties, a new structure of BC_2N potential superhard compound with tetragonal symmetry structure and space group of I4/mmm was constructed in this paper. Using the first-principles calculation method based on density functional theory, the thermodynamic, mechanical and dynamic stability of the new tetragonal phase structure of the compound was systematically studied. It is shown that the tetragonal phase BC_2N is atable in mechanics and dynamics at least in the pressure range of 0–60 GPa. The thermodynamic calculation results show that the structural formation energy is slightly higher than the most stable wurtzite structure in the BC2 N compound, indicating that the newly constructed tetragonal structure is a metastable structure of the BC_2N compound, and its incompressibility is greater than other boron-carbon-nitrogen materials such as B_2CN and BC_4N.Based on the structural stability study, the electronic structure of the tetragonal BC2 N in the pressure range of 0–60 GPa is calculated. It is found to have a bandwidth of 2.16 e Vat zero pressure, which is a semiconductor, and with the increase of pressure, The band gap is gradually widened; the high-pressure elastic properties show that the bulk modulus, shear modulus, Young's modulus, Poisson's ratio, Debye temperature, minimum thermal conductivity and elastic wave velocity of the tetragonal structure of BC_2N compound are all increased in different increasing tendency with pressure, it shows brittleness and its elastic anisotropy becomes more obvious under high pressure. At the same time, the large bulk modulus, large shear modulus and high Vickers hardness indicate that the constructed tetragonal structure with I4/mmm space group is a potential superhard new structure of BC_2N compounds.
Light elements boron(B), carbon(C) and nitrogen(N) have small atomic radius and strong bonding ability, and the formed compounds are easy to form strong covalent bonds and high atomic density three-dimensional networks structures, makes it an alternative system for the preparation of superhard materials. Based on the newly studied bodycentered tetragonal carbon structure model with excellent mechanical properties, a new structure of BC_2N potential superhard compound with tetragonal symmetry structure and space group of I4/mmm was constructed in this paper. Using the first-principles calculation method based on density functional theory, the thermodynamic, mechanical and dynamic stability of the new tetragonal phase structure of the compound was systematically studied. It is shown that the tetragonal phase BC_2N is atable in mechanics and dynamics at least in the pressure range of 0–60 GPa. The thermodynamic calculation results show that the structural formation energy is slightly higher than the most stable wurtzite structure in the BC2 N compound, indicating that the newly constructed tetragonal structure is a metastable structure of the BC_2N compound, and its incompressibility is greater than other boron-carbon-nitrogen materials such as B_2CN and BC_4N.Based on the structural stability study, the electronic structure of the tetragonal BC2 N in the pressure range of 0–60 GPa is calculated. It is found to have a bandwidth of 2.16 e Vat zero pressure, which is a semiconductor, and with the increase of pressure, The band gap is gradually widened; the high-pressure elastic properties show that the bulk modulus, shear modulus, Young's modulus, Poisson's ratio, Debye temperature, minimum thermal conductivity and elastic wave velocity of the tetragonal structure of BC_2N compound are all increased in different increasing tendency with pressure, it shows brittleness and its elastic anisotropy becomes more obvious under high pressure. At the same time, the large bulk modulus, large shear modulus and high Vickers hardness indicate that the constructed tetragonal structure with I4/mmm space group is a potential superhard new structure of BC_2N compounds.
引文
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7 Nakano S,Akaishi M,Sasaki T,et al.Segregative crystallization of several diamond-like phases from the graphitic BC2N without an additive at7.7 GPa.Chem Mater,1994,6:2246-2251
8 Knittle E,Kaner R B,Jeanloz R,et al.High-pressure synthesis,characterization,and equation of state of cubic C-BN solid solutions.Phys Rev B,1995,51:12149-12156
9 Komatsu T,Nomura M,Kakudate Y,et al.Synthesis and characterization of a shock-synthesized cubic B-C-N solid solution of composition BC2.5N.J Mater Chem,1996,6:1799-1803
10 He J L,Tian Y J,Yu D L,et al.Orthorhombic B2CN crystal synthesized by high pressure and temperature.Chem Phys Lett,2001,340:431-436
11 Zhao Y,He D W,Daemen L L,et al.Superhard B-C-N materials synthesized in nanostructured bulks.J Mater Res,2002,17:3139-3145
12 Solozhenko V L,Andrault D,Fiquet G,et al.Synthesis of superhard cubic BC2N.Appl Phys Lett,2001,78:1385-1387
13 Zang C P,Sun H.Chemical anisotropy in diamondlike BC N2:First-principles calculations.Phys Rev B,2010,81:012106
14 Luo X,Guo X,Liu Z,et al.First-principles study of wurtzite BC N2.Phys Rev B,2007,76:092107
15 Sun J,Zhou X F,Qian G R,et al.Chalcopyrite polymorph for superhard BC2N.Appl Phys Lett,2006,89:151911
16 Zhou X F,Sun J,Fan Y X,et al.Most likely phase of superhard BC N2by ab initio calculations.Phys Rev B,2007,76:100101
17 Zhou X F,Sun J,Qian Q R,et al.A tetragonal phase of superhard BC2N.J Appl Phys,2009,105:093521
18 Chen Z Q,Li C M,Wang J,et al.Theoretical study of mechanical properties and electronic structures of several BC2N superhard materials(in Chinese).Sci Sin-Phys Mech Astron,2013,43:142-151[陈志谦,李春梅,王8),等.几种BC2N超硬材料力学性能与电子结构的理论研究.中国科学:物理学力学天文学,2013,43:142-151]
19 Qin Y,Shi L,Zhang S,et al.Effects of biaxial strains on the structural,electronic,elastic and lattice vibrational properties in t-BC2N and z-BC2N.J Alloys Compd,2016,686:914-922
20 Lu J,Gao S P.Theoretical ELNES fingerprints of BC2N polytypes.Comput Mater Sci,2013,68:335-341
21 Ao J,Li C M,Wang J,et al.Investigations of elastic and anisotropic of new superhard material R3m-BC2N(in Chinese).Sci Sin-Phys Mech Astron,2013,43:1065-1073[敖靖,李春梅,王8),等.新型超硬材料R3m-BC2N的弹性及其各向异性的研究.中国科学:物理学力学天文学,2013,43:1065-1073]
22 Li Q,Zhou D,Wang H,et al.Crystal and electronic structures of superhard B2CN:An ab initio study.Solid State Commun,2012,152:71-75
23 Zhang X,Wang Y,Lv J,et al.First-principles structural design of superhard materials.J Chem Phys,2013,138:114101
24 Li F,Man Y H,Li C M,et al.Mechanical properties,minimum thermal conductivity,and anisotropy in bc-structure superhard materials.Comput Mater Sci,2015,102:327-337
25 Wang D,Shi R,Gan L H.t-C8B2N2:A potential superhard material.Chem Phys Lett,2017,669:80-84
26 Basalaev Y M,Kopytov AV,Pavlova T Y,et al.Ab initio and phenomenological modeling of the phonon spectrum of superhard cp-BC2N.Russ Phys J,2015,58:978-986
27 Fan Q,Wei Q,Chai C,et al.Elastic and electronic properties of Imm2-and I4m2-BCN.Comput Mater Sci,2015,97:6-13
28 Zhang R F,Lin Z J,Veprek S.Anisotropic ideal strengths of superhard monoclinic and tetragonal carbon and their electronic origin.Phys Rev B,2011,83:155452
29 Segall M D,Lindan P J D,Probert M J,et al.First-principles simulation:Ideas,illustrations and the CASTEP code.J Phys-Condens Matter,2002,14:2717-2744
30 Perdew J P,Ruzsinszky A,Csonka G I,et al.Restoring the density-gradient expansion for exchange in solids and surfaces.Phys Rev Lett,2008,100:136406,arXiv:0707.2088
31 Vanderbilt D.Soft self-consistent pseudopotentials in a generalized eigenvalue formalism.Phys Rev B,1990,41:7892-7895
32 Monkhorst H J,Pack J D.Special points for Brillouin-zone integrations.Phys Rev B,1976,13:5188-5192
33 Fischer T H,Almlof J.General methods for geometry and wave function optimization.J Phys Chem,1992,96:9768-9774
34 Gonze X,Lee C.Dynamical matrices,Born effective charges,dielectric permittivity tensors,and interatomic force constants from densityfunctional perturbation theory.Phys Rev B,1997,55:10355-10368
35 Karki B B,Ackland G J,Crain J.Elastic instabilities in crystals from ab initio stress-strain relations.J Phys-Condens Matter,1997,9:8579-8589
36 Hill R.The elastic behaviour of a crystalline aggregate.Proc Phys Soc A,1952,65:349-354
37 Fan Q,Wei Q,Chai C,et al.Structural,mechanical,and electronic properties of P3m1-BCN.J Phys Chem Solids,2015,79:89-96
38 Oganov A R,Chen J,Gatti C,et al.Ionic high-pressure form of elemental boron.Nature,2009,457:863-867,arXiv:0911.3192
39 Yamada K,Tanabe Y.Shock-induced phase transition of oriented pyrolytic graphite to diamond at pressures up to 15 GPa.Carbon,2002,40:261-269
40 Pickard C J,Needs R J.High-pressure phases of nitrogen.Phys Rev Lett,2009,102:125702
41 Olijnyk H.High pressure X-ray diffraction studies on solid N2up to 43.9 GPa.J Chem Phys,1990,93:8968-8972
42 Wang X,Tian F,Wang L,et al.Structural stability of polymeric nitrogen:A first-principles investigation.J Chem Phys,2010,132:024502
43 Wu Z J,Zhao E J,Xiang H P,et al.Crystal structures and elastic properties of superhard Ir N2and Ir N3from first principles.Phys Rev B,2007,76:054115
44 Sun X W,Bioud N,Fu Z J,et al.High-pressure elastic properties of cubic Ir2P from ab initio calculations.Phys Lett A,2016,380:3672-3677
45 Pugh S F.XCII.Relations between the elastic moduli and the plastic properties of polycrystalline pure metals.London Edinburgh Dublin Philos Mag J Sci,1954,45:823-843
46 Feng W,Cui S,Hu H,et al.First-principles study on electronic structure and elastic properties of hexagonal Zr2Sc.Phys B-Cond Matter,2010,405:4294-4298
47 Zhang G,Zhao Y,Bai T,et al.A new hard phase and physical properties of Tc2C predicted from first principles.RSC Adv,2016,6:66066-66073
48 Ranganathan S I,Ostoja-Starzewski M.Universal elastic anisotropy index.Phys Rev Lett,2008,101:055504
49 Ahmed R,Fazal-e-Aleem R,Hashemifar S J,et al.First principles study of structural and electronic properties of different phases of boron nitride.Phys B-Cond Matter,2007,400:297-306
50 Cahill D G,Watson S K,Pohl R O.Lower limit to the thermal conductivity of disordered crystals.Phys Rev B,1992,46:6131-6140
51 Anderson O L.A simplified method for calculating the Debye temperature from elastic constants.J Phys Chem Solids,1963,24:909-917
52 Panda K B,Chandran K S R.Determination of elastic constants of titanium diboride(TiB2)from first principles using FLAPW implementation of the density functional theory.Comput Mater Sci,2006,35:134-150
53 Chen X Q,Niu H,Li D,et al.Modeling hardness of polycrystalline materials and bulk metallic glasses.Intermetallics,2011,19:1275-1281
2 Liang Y,Li C,Guo W,et al.First-principles investigation of technetium carbides and nitrides.Phys Rev B,2009,79:024111
3 Nassau K,Nassau J.The history and present status of synthetic diamond.J Cryst Growth,1979,46:157-172
4 Gao F,He J,Wu E,et al.Hardness of covalent crystals.Phys Rev Lett,2003,91:015502
5 Xu B,Tian Y J.High pressure synthesis of nanotwinned ultrahard materials(in Chinese).Acta Phys Sin,2016,66:36201[徐波,田永君.纳米孪晶超硬材料的高压合成.物理学报,2016,66:36201]
6 Liu Y J,He D W,Wang P,et al.Syntheses and studies of superhard composites under high pressure(in Chinese).Acta Phys Sin,2017,66:38103[刘银娟,贺端威,王培,等.复合超硬材料的高压合成与研究.物理学报,2017,66:38103]
7 Nakano S,Akaishi M,Sasaki T,et al.Segregative crystallization of several diamond-like phases from the graphitic BC2N without an additive at7.7 GPa.Chem Mater,1994,6:2246-2251
8 Knittle E,Kaner R B,Jeanloz R,et al.High-pressure synthesis,characterization,and equation of state of cubic C-BN solid solutions.Phys Rev B,1995,51:12149-12156
9 Komatsu T,Nomura M,Kakudate Y,et al.Synthesis and characterization of a shock-synthesized cubic B-C-N solid solution of composition BC2.5N.J Mater Chem,1996,6:1799-1803
10 He J L,Tian Y J,Yu D L,et al.Orthorhombic B2CN crystal synthesized by high pressure and temperature.Chem Phys Lett,2001,340:431-436
11 Zhao Y,He D W,Daemen L L,et al.Superhard B-C-N materials synthesized in nanostructured bulks.J Mater Res,2002,17:3139-3145
12 Solozhenko V L,Andrault D,Fiquet G,et al.Synthesis of superhard cubic BC2N.Appl Phys Lett,2001,78:1385-1387
13 Zang C P,Sun H.Chemical anisotropy in diamondlike BC N2:First-principles calculations.Phys Rev B,2010,81:012106
14 Luo X,Guo X,Liu Z,et al.First-principles study of wurtzite BC N2.Phys Rev B,2007,76:092107
15 Sun J,Zhou X F,Qian G R,et al.Chalcopyrite polymorph for superhard BC2N.Appl Phys Lett,2006,89:151911
16 Zhou X F,Sun J,Fan Y X,et al.Most likely phase of superhard BC N2by ab initio calculations.Phys Rev B,2007,76:100101
17 Zhou X F,Sun J,Qian Q R,et al.A tetragonal phase of superhard BC2N.J Appl Phys,2009,105:093521
18 Chen Z Q,Li C M,Wang J,et al.Theoretical study of mechanical properties and electronic structures of several BC2N superhard materials(in Chinese).Sci Sin-Phys Mech Astron,2013,43:142-151[陈志谦,李春梅,王8),等.几种BC2N超硬材料力学性能与电子结构的理论研究.中国科学:物理学力学天文学,2013,43:142-151]
19 Qin Y,Shi L,Zhang S,et al.Effects of biaxial strains on the structural,electronic,elastic and lattice vibrational properties in t-BC2N and z-BC2N.J Alloys Compd,2016,686:914-922
20 Lu J,Gao S P.Theoretical ELNES fingerprints of BC2N polytypes.Comput Mater Sci,2013,68:335-341
21 Ao J,Li C M,Wang J,et al.Investigations of elastic and anisotropic of new superhard material R3m-BC2N(in Chinese).Sci Sin-Phys Mech Astron,2013,43:1065-1073[敖靖,李春梅,王8),等.新型超硬材料R3m-BC2N的弹性及其各向异性的研究.中国科学:物理学力学天文学,2013,43:1065-1073]
22 Li Q,Zhou D,Wang H,et al.Crystal and electronic structures of superhard B2CN:An ab initio study.Solid State Commun,2012,152:71-75
23 Zhang X,Wang Y,Lv J,et al.First-principles structural design of superhard materials.J Chem Phys,2013,138:114101
24 Li F,Man Y H,Li C M,et al.Mechanical properties,minimum thermal conductivity,and anisotropy in bc-structure superhard materials.Comput Mater Sci,2015,102:327-337
25 Wang D,Shi R,Gan L H.t-C8B2N2:A potential superhard material.Chem Phys Lett,2017,669:80-84
26 Basalaev Y M,Kopytov AV,Pavlova T Y,et al.Ab initio and phenomenological modeling of the phonon spectrum of superhard cp-BC2N.Russ Phys J,2015,58:978-986
27 Fan Q,Wei Q,Chai C,et al.Elastic and electronic properties of Imm2-and I4m2-BCN.Comput Mater Sci,2015,97:6-13
28 Zhang R F,Lin Z J,Veprek S.Anisotropic ideal strengths of superhard monoclinic and tetragonal carbon and their electronic origin.Phys Rev B,2011,83:155452
29 Segall M D,Lindan P J D,Probert M J,et al.First-principles simulation:Ideas,illustrations and the CASTEP code.J Phys-Condens Matter,2002,14:2717-2744
30 Perdew J P,Ruzsinszky A,Csonka G I,et al.Restoring the density-gradient expansion for exchange in solids and surfaces.Phys Rev Lett,2008,100:136406,arXiv:0707.2088
31 Vanderbilt D.Soft self-consistent pseudopotentials in a generalized eigenvalue formalism.Phys Rev B,1990,41:7892-7895
32 Monkhorst H J,Pack J D.Special points for Brillouin-zone integrations.Phys Rev B,1976,13:5188-5192
33 Fischer T H,Almlof J.General methods for geometry and wave function optimization.J Phys Chem,1992,96:9768-9774
34 Gonze X,Lee C.Dynamical matrices,Born effective charges,dielectric permittivity tensors,and interatomic force constants from densityfunctional perturbation theory.Phys Rev B,1997,55:10355-10368
35 Karki B B,Ackland G J,Crain J.Elastic instabilities in crystals from ab initio stress-strain relations.J Phys-Condens Matter,1997,9:8579-8589
36 Hill R.The elastic behaviour of a crystalline aggregate.Proc Phys Soc A,1952,65:349-354
37 Fan Q,Wei Q,Chai C,et al.Structural,mechanical,and electronic properties of P3m1-BCN.J Phys Chem Solids,2015,79:89-96
38 Oganov A R,Chen J,Gatti C,et al.Ionic high-pressure form of elemental boron.Nature,2009,457:863-867,arXiv:0911.3192
39 Yamada K,Tanabe Y.Shock-induced phase transition of oriented pyrolytic graphite to diamond at pressures up to 15 GPa.Carbon,2002,40:261-269
40 Pickard C J,Needs R J.High-pressure phases of nitrogen.Phys Rev Lett,2009,102:125702
41 Olijnyk H.High pressure X-ray diffraction studies on solid N2up to 43.9 GPa.J Chem Phys,1990,93:8968-8972
42 Wang X,Tian F,Wang L,et al.Structural stability of polymeric nitrogen:A first-principles investigation.J Chem Phys,2010,132:024502
43 Wu Z J,Zhao E J,Xiang H P,et al.Crystal structures and elastic properties of superhard Ir N2and Ir N3from first principles.Phys Rev B,2007,76:054115
44 Sun X W,Bioud N,Fu Z J,et al.High-pressure elastic properties of cubic Ir2P from ab initio calculations.Phys Lett A,2016,380:3672-3677
45 Pugh S F.XCII.Relations between the elastic moduli and the plastic properties of polycrystalline pure metals.London Edinburgh Dublin Philos Mag J Sci,1954,45:823-843
46 Feng W,Cui S,Hu H,et al.First-principles study on electronic structure and elastic properties of hexagonal Zr2Sc.Phys B-Cond Matter,2010,405:4294-4298
47 Zhang G,Zhao Y,Bai T,et al.A new hard phase and physical properties of Tc2C predicted from first principles.RSC Adv,2016,6:66066-66073
48 Ranganathan S I,Ostoja-Starzewski M.Universal elastic anisotropy index.Phys Rev Lett,2008,101:055504
49 Ahmed R,Fazal-e-Aleem R,Hashemifar S J,et al.First principles study of structural and electronic properties of different phases of boron nitride.Phys B-Cond Matter,2007,400:297-306
50 Cahill D G,Watson S K,Pohl R O.Lower limit to the thermal conductivity of disordered crystals.Phys Rev B,1992,46:6131-6140
51 Anderson O L.A simplified method for calculating the Debye temperature from elastic constants.J Phys Chem Solids,1963,24:909-917
52 Panda K B,Chandran K S R.Determination of elastic constants of titanium diboride(TiB2)from first principles using FLAPW implementation of the density functional theory.Comput Mater Sci,2006,35:134-150
53 Chen X Q,Niu H,Li D,et al.Modeling hardness of polycrystalline materials and bulk metallic glasses.Intermetallics,2011,19:1275-1281