压力作用下Cr_2AC相(A=Si、Ge)的第一性原理研究
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摘要
采用基于密度泛函理论的第一性原理方法,研究了高压下Cr_2AC相(A=Si、Ge)的力学性能和电子结构特点。结果表明:0～80 GPa范围内,Cr_2SiC和Cr_2GeC的晶格常数a、c和体积V均随压力增加而下降,a轴方向上比c轴方向上更容易被压缩;弹性性质计算结构表明在0～80 GPa范围内两个化合物均是力学稳定的,弹性模量(体积模量B、剪切模量G)随着压力的不断增加而增大,说明增加压力可以使两个化合物的硬度提高;此外,还从电子态密度的角度考察了Cr_2Si C和Cr_2GeC的电子性质,在0～80 GPa范围内,压力对整体态密度影响较小,费米能级处的电子态密度值随着压力的不断增加而降低,说明增加压力能够提高两个化合物的稳定性。
The mechanical properties and electronic structure characteristics of the Cr_2 AC phase( A = Si,Ge) at high pressure were studied using the first-principles method based on density functional theory.The results show that the lattice constants a,c and volume V of Cr_2SiC and Cr_2 GeC decrease with increasing pressure in the range of 0-80 GPa,and are more easily compressed in the a-axis direction than in the c-axis direction. The calculation of the elastic properties shows that both compounds are mechanical stable within the range of 0-80 GPa,The elastic modulus( volume modulus B,shear modulus G)increases with the increasing pressure,indicating that the increasing pressure can improve the hardness of the two compounds. In addition,the electronic properties of Cr_2 SiC and Cr_2 GeC are investigated from the perspective of electronic density,in the range of 0-80 GPa,the pressure has less influence on the density of the whole state. The value of the electronic density at the Fermi level decreases with the increase of pressure,indicating that increasing the pressure can be improve the stability of the two compounds.
The mechanical properties and electronic structure characteristics of the Cr_2 AC phase( A = Si,Ge) at high pressure were studied using the first-principles method based on density functional theory.The results show that the lattice constants a,c and volume V of Cr_2SiC and Cr_2 GeC decrease with increasing pressure in the range of 0-80 GPa,and are more easily compressed in the a-axis direction than in the c-axis direction. The calculation of the elastic properties shows that both compounds are mechanical stable within the range of 0-80 GPa,The elastic modulus( volume modulus B,shear modulus G)increases with the increasing pressure,indicating that the increasing pressure can improve the hardness of the two compounds. In addition,the electronic properties of Cr_2 SiC and Cr_2 GeC are investigated from the perspective of electronic density,in the range of 0-80 GPa,the pressure has less influence on the density of the whole state. The value of the electronic density at the Fermi level decreases with the increase of pressure,indicating that increasing the pressure can be improve the stability of the two compounds.
引文
[1]Barsoum M W.Mn+1AXnphases:a new class of solids;thermodynamically stable nanolaminates[J].Progress in Solid State Chemistry,2000,28(1):201-281.
[2]Bai Y,Srikanth N,Chua C K,et al.Density functional theory study of Mn+1AXnphases:a review[J].Critical Reviews in Solid State&Material Sciences,2017(6):1-51.
[3]Mo Y,Rulis P,Ching W Y.Electronic structure and interband optical properties of 20 MAX phase compounds[C].International Conference&Exposition on Advanced Ceramics&Composites,American Ceramic Society,2012.
[4]Jeitschko W,Nowotny H,Benesovsky F.Kohlenstoffhaltige ternare Verbindungen(V-Ge-C,Nb-Ga-C,Ta-Ga-C,Ta-Ge-C,Cr-Ga-C und CrGe-C)[J].Monatshefte Für Chemie Und Verwandte Teile Anderer Wissenschaften,1963,94(5):844-850.
[5]Amini S,Zhou A,Gupta S,et al.Synthesis and elastic and mechanical properties of Cr2Ge C[J].Journal of Materials Research,2008,23(8):2157-2165.
[6]Eklund P,Bugnet M,Mauchamp V,et al.Epitaxial growth and electrical transport properties of Cr2Ge C thin films[J].Physical Review B,2011,84(7):075424.
[7]Zhou W,Liu L,Wu P.First-principles study of structural,thermodynamic,elastic,and magnetic properties of Cr2Ge C under pressure and temperature[J].Journal of Applied Physics,2009,106(3):1953.
[8]Faraoun H I,Abderrahim F Z,Esling C.First principle calculations of MAX ceramics Cr2Ge C,V2Ge C and their substitutional solid solutions[J].Computational Materials Science,2013,74:40-49.
[9]Xiao J,Yang T,Wang C,et al.Investigations on radiation tolerance of Mn+1AXnphases:study of Ti3SiC2,Ti3Al C2,Cr2Al C,Cr2Ge C,Ti2Al C,and Ti2Al N[J].Journal of the American Ceramic Society,2015,98(4):1323-1331.
[10]Ghebouli M A,Ghebouli B,Fatmi M,et al.Theoretical prediction of the structural,elastic,electronic and thermal properties of the MAX phases X2SiC(=and)[J].Intermetallics,2011,19(12):1936-1942.
[11]Milman V,Refson K,Clark S J,et al.Electron and vibrational spectroscopies using DFT,plane waves and pseudopotentials:CASTEPimplementation[J].Journal of Molecular Structure Theochem,2010,954(1):22-35.
[12]Vanderbilt D.Soft self-consistent pseudopotentials in a generalized eigenvalue formalism[J].Physical Review B Condensed Matter,1990,41(11):7892.
[13]Ceperley D M,Alder B J.Ground State of the electron gas by a stochastic method[J].Physical Review Letters,1980,45(7):566-569.
[14]Perdew J P,Mcmullen E R,Zunger A.Density-functional theory of the correlation energy in atoms and ions:a simple analytic model and a challenge[J].Physical Review A,1981,23(6):2785-2789.
[15]Burke J P P,K,And M E.Local and gradient-corrected density functionals[M].Local and Gradient-Corrected Density Functionals,1996:453-462.
[16]Li N,Mo Y,Ching W Y.Retraction:"The bonding,charge distribution,spin ordering,optical,and elastic properties of four MAX phases Cr2AX(A=Al or Ge,X=C or N):From density functional theory study"[J].Journal of Applied Physics,2013,114(18):183503.
[17]Manoun B,Amini S,Gupta S,et al.On the compression behavior of Cr2Ge C and V2Ge C up to quasi-hydrostatic pressures of 50 GPa[J].Journal of Physics Condensed Matter,2007,19(45):456218.
[18]Born M.On the stability of crystal lattices[J].Mathematical Proceedings of the Cambridge Philosophical Society,1940,36(2):160-172.
[19]Hill R W.The elastic behavior of a crystalline aggregate[J].Proceedings of the Physical Society,1952,65(5):349-354.
[20]Pugh S F.XCII.Relations between the elastic moduli and the plastic properties of polycrystalline pure metals[J].Philosophical Magazine,2009,45(367):823-843.
[21]Mattesini M,Magnuson M,Tasnádi F,et al.Elastic properties and electrostructural correlations in ternary scandium-based cubic inverse perovskites:A first-principles study[J].Physical Review B Condensed Matter,2009,79(12):125122.
[22]Chen Q,Huang Z,Zhao Z,et al.Thermal stabilities,elastic properties and electronic structures of B2-MgRE(RE=Sc,Y,La)by firstprinciples calculations[J].Computational Materials Science,2013,67:196-202.
[2]Bai Y,Srikanth N,Chua C K,et al.Density functional theory study of Mn+1AXnphases:a review[J].Critical Reviews in Solid State&Material Sciences,2017(6):1-51.
[3]Mo Y,Rulis P,Ching W Y.Electronic structure and interband optical properties of 20 MAX phase compounds[C].International Conference&Exposition on Advanced Ceramics&Composites,American Ceramic Society,2012.
[4]Jeitschko W,Nowotny H,Benesovsky F.Kohlenstoffhaltige ternare Verbindungen(V-Ge-C,Nb-Ga-C,Ta-Ga-C,Ta-Ge-C,Cr-Ga-C und CrGe-C)[J].Monatshefte Für Chemie Und Verwandte Teile Anderer Wissenschaften,1963,94(5):844-850.
[5]Amini S,Zhou A,Gupta S,et al.Synthesis and elastic and mechanical properties of Cr2Ge C[J].Journal of Materials Research,2008,23(8):2157-2165.
[6]Eklund P,Bugnet M,Mauchamp V,et al.Epitaxial growth and electrical transport properties of Cr2Ge C thin films[J].Physical Review B,2011,84(7):075424.
[7]Zhou W,Liu L,Wu P.First-principles study of structural,thermodynamic,elastic,and magnetic properties of Cr2Ge C under pressure and temperature[J].Journal of Applied Physics,2009,106(3):1953.
[8]Faraoun H I,Abderrahim F Z,Esling C.First principle calculations of MAX ceramics Cr2Ge C,V2Ge C and their substitutional solid solutions[J].Computational Materials Science,2013,74:40-49.
[9]Xiao J,Yang T,Wang C,et al.Investigations on radiation tolerance of Mn+1AXnphases:study of Ti3SiC2,Ti3Al C2,Cr2Al C,Cr2Ge C,Ti2Al C,and Ti2Al N[J].Journal of the American Ceramic Society,2015,98(4):1323-1331.
[10]Ghebouli M A,Ghebouli B,Fatmi M,et al.Theoretical prediction of the structural,elastic,electronic and thermal properties of the MAX phases X2SiC(=and)[J].Intermetallics,2011,19(12):1936-1942.
[11]Milman V,Refson K,Clark S J,et al.Electron and vibrational spectroscopies using DFT,plane waves and pseudopotentials:CASTEPimplementation[J].Journal of Molecular Structure Theochem,2010,954(1):22-35.
[12]Vanderbilt D.Soft self-consistent pseudopotentials in a generalized eigenvalue formalism[J].Physical Review B Condensed Matter,1990,41(11):7892.
[13]Ceperley D M,Alder B J.Ground State of the electron gas by a stochastic method[J].Physical Review Letters,1980,45(7):566-569.
[14]Perdew J P,Mcmullen E R,Zunger A.Density-functional theory of the correlation energy in atoms and ions:a simple analytic model and a challenge[J].Physical Review A,1981,23(6):2785-2789.
[15]Burke J P P,K,And M E.Local and gradient-corrected density functionals[M].Local and Gradient-Corrected Density Functionals,1996:453-462.
[16]Li N,Mo Y,Ching W Y.Retraction:"The bonding,charge distribution,spin ordering,optical,and elastic properties of four MAX phases Cr2AX(A=Al or Ge,X=C or N):From density functional theory study"[J].Journal of Applied Physics,2013,114(18):183503.
[17]Manoun B,Amini S,Gupta S,et al.On the compression behavior of Cr2Ge C and V2Ge C up to quasi-hydrostatic pressures of 50 GPa[J].Journal of Physics Condensed Matter,2007,19(45):456218.
[18]Born M.On the stability of crystal lattices[J].Mathematical Proceedings of the Cambridge Philosophical Society,1940,36(2):160-172.
[19]Hill R W.The elastic behavior of a crystalline aggregate[J].Proceedings of the Physical Society,1952,65(5):349-354.
[20]Pugh S F.XCII.Relations between the elastic moduli and the plastic properties of polycrystalline pure metals[J].Philosophical Magazine,2009,45(367):823-843.
[21]Mattesini M,Magnuson M,Tasnádi F,et al.Elastic properties and electrostructural correlations in ternary scandium-based cubic inverse perovskites:A first-principles study[J].Physical Review B Condensed Matter,2009,79(12):125122.
[22]Chen Q,Huang Z,Zhao Z,et al.Thermal stabilities,elastic properties and electronic structures of B2-MgRE(RE=Sc,Y,La)by firstprinciples calculations[J].Computational Materials Science,2013,67:196-202.