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采用密度泛函理论中的赝势平面波方法研究了高压下超导材料 ErNi2B2C 的弹性性质、电子结构和热力学性质.分析表明, 弹性常数、体弹模量、剪切模量、杨氏模量和弹性各向异性因子的外压力效应明显. 电子态密度(DOS)的计算结果显示, 在费米能级(EF)处的 DOS 峰随外界压强的增大显著降低, 由于 ErNi2B2C 相对较高的超导温度(Tc)起因于EF处的 DOS 峰, 因此推测压强增大可能会降低 ErNi2B2C 的 Tc.类似的现象在超导材料 MgB2和 SrAlSi 中已被发现.此外, 基于准谐德拜模型, 对 ErNi2B2C 在高温高压下的热力学性质的研究表明, 在一定范围内, 温度和压强将对其热膨胀系数和热容产生明显的影响.The elastic, electronic and thermodynamic properties of the superconducting ErNi2B2C material at high pressure are investigated using the plane-wave pseudopotential density functional theory. The analysis shows the dependences of the elastic constants, bulk modulus, shear modulus, Young's modulus and elastic anisotropy factors on the applied pressure. The calculated electronic density of states (DOS) reveals that the DOS peak at the Fermi level (EF) will decrease noticeably with pressure. It can be concluded that the pressure may reduce the superconducting temperature (Tc) of ErNi2B2C since the relatively high Tc originates from the peak in the DOS. This phenomenon is also found in some other superconductors such as MgB2 and SrAlSi. Moreover, based on the quasi-harmonic Debye model, the results of the thermodynamic properties indicate that the pressure and temperature have significant influences on the thermal expansion coefficient and heat capacity.
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Keywords:
- high pressure /
- elastic properties /
- electronic structure /
- thermodynamic properties
[1] Cava R J, Takagi H, Zandbergen H W, Krajewski J J, Peck Jr W F, Siegrist T, Batlogg B, van Dover R B, Felder R J, Mizuhashi K, Lee J O, Eisaki H, Uchida S 1994 Nature 367 252
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[18] Jiao Z Y, Yang J F, Zhang X Z, Ma S H, Guo Y L 2011 Acta Phys. Sin. 60 117103 (in Chinese) [焦照勇, 杨继飞, 张现周, 马淑红, 郭永亮 2011 60 117103]
[19] Li S N, Liu Y 2010 Acta Phys. Sin. 59 6882 (in Chinese) [李世娜, 刘 永 2010 59 6882]
[20] Zhang W, Chen W Z, Wang J F, Zhang X D, Jiang Z Y 2012 Acta Phys. Sin. 61 246201 (in Chinese) [张 炜, 陈文周, 王俊斐, 张小东, 姜振益 2012 61 246201]
[21] Chen H C, Yang L J 2011 Acta Phys. Sin. 60 014207 (in Chinese) [陈海川, 杨利君 2011 60 014207]
[22] Blanco M A, Francisco E, Luana V 2004 Comp. Phys. Commun. 158 57
[23] Lynn J W, Skanthakumar S, Huang Q, Sinha S K, Hossain Z, Gupta L C, Nagarajan R, Godart C 1997 Phys. Rev. B 55 6584
[24] Ranganathan S I, Ostoja-Starzewski M 2008 Phys. Rev. Lett. 101 055504
[25] Chung D H, Buessem W R 1968 edited by Vahldiek F W, Mersol S A Anisotropy in Single Crystal Refractory Compound (Vol.2) (New York: Plenum) p217
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[28] Weht R, Cappannini O M, Rodríguez C O, Christensen N E 1996 Physica C 260 125
[29] Ravindran P, Fast L, PKorzhavyi. A, Johansson B, Wills J, Eriksson O 1998 J. Appl. Phys. 84 4891
[30] Calegari E J, Magalhães S G, Chaves C M, Troper A 2011 Supercond. Sci. Technol. 24 035004
[31] Wang Y C, Lü J, Ma Y M, Cui T, Zou G T 2009 Phys. Rev. B 80 092505
[32] Lorenz B, Cmaidalka J, Meng R L, Chu C W 2003 Phys. Rev. B 68 014512
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[1] Cava R J, Takagi H, Zandbergen H W, Krajewski J J, Peck Jr W F, Siegrist T, Batlogg B, van Dover R B, Felder R J, Mizuhashi K, Lee J O, Eisaki H, Uchida S 1994 Nature 367 252
[2] Siegrist T, Zandbergen H W, Cava R J, Krajewski J J, Peck Jr W F 1994 Nature 367 254
[3] Cho B K, Canfield P C, Johnston D C 1995 Phys. Rev. B 52 3844
[4] Pickett W E, Singh D J 1994 Phys. Rev. Lett. 72 3702
[5] Mattheiss L F 1994 Phys. Rev. B 49 13279
[6] Hoellwarth C C, Klavins P, Shelton R N 1996 Phys. Rev. B 53 2579
[7] Sánchez D R, Micklitz H, Baggio-Saitovitch E M 2005 Phys. Rev. B 71 024509
[8] Canfield P C, Gammel P L, Bishop D J 1998 Phys. Today 51 40
[9] Bud'ko S, Canfield P 2006 C. R. Phys. 7 56
[10] Choi S M, Lynn J W, Lopez J W, Gammel P L, Canfield P C, Bud'ko S L 2001 Phys. Rev. Lett. 87 107001
[11] Kawano-Furukawa H, Takeshita H, Ochiai M, Nagata T, Yoshizawa H, Furukawa N, Takeya H, Kadowaki K 2002 Phys. Rev. B 65 180508
[12] Schmidt H, Braun H F 1994 Physica C 229 315
[13] Alleno E, Neumeier J J, Thompson J D, Canfield P C, Cho B K 1995 Physica C 242 169
[14] Kresse G, Hafner J 1993 Phys. Rev. B 47 558
[15] Kresse G, Furthmller J 1996 Phys. Rev. B 54 11169
[16] Perdew J P, Chevary J A, Vosko S H, Jackson K A, Pederson M R, Singh D J, Fiolhais C 1992 Phys. Rev. B 46 6671
[17] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865
[18] Jiao Z Y, Yang J F, Zhang X Z, Ma S H, Guo Y L 2011 Acta Phys. Sin. 60 117103 (in Chinese) [焦照勇, 杨继飞, 张现周, 马淑红, 郭永亮 2011 60 117103]
[19] Li S N, Liu Y 2010 Acta Phys. Sin. 59 6882 (in Chinese) [李世娜, 刘 永 2010 59 6882]
[20] Zhang W, Chen W Z, Wang J F, Zhang X D, Jiang Z Y 2012 Acta Phys. Sin. 61 246201 (in Chinese) [张 炜, 陈文周, 王俊斐, 张小东, 姜振益 2012 61 246201]
[21] Chen H C, Yang L J 2011 Acta Phys. Sin. 60 014207 (in Chinese) [陈海川, 杨利君 2011 60 014207]
[22] Blanco M A, Francisco E, Luana V 2004 Comp. Phys. Commun. 158 57
[23] Lynn J W, Skanthakumar S, Huang Q, Sinha S K, Hossain Z, Gupta L C, Nagarajan R, Godart C 1997 Phys. Rev. B 55 6584
[24] Ranganathan S I, Ostoja-Starzewski M 2008 Phys. Rev. Lett. 101 055504
[25] Chung D H, Buessem W R 1968 edited by Vahldiek F W, Mersol S A Anisotropy in Single Crystal Refractory Compound (Vol.2) (New York: Plenum) p217
[26] Rourke P M C, Paglione J, Ronning F, Taillefer L, Kadowaki K 2003 Physica C 397 1
[27] Meenakshi S, Vijayakumar V, Rao R S, Sikka B K, Ravindran P, Hossain Z, Nagarajan R, Gupta L C, Vijayaraghavan R 1998 Phys. Rev. B 58 3377
[28] Weht R, Cappannini O M, Rodríguez C O, Christensen N E 1996 Physica C 260 125
[29] Ravindran P, Fast L, PKorzhavyi. A, Johansson B, Wills J, Eriksson O 1998 J. Appl. Phys. 84 4891
[30] Calegari E J, Magalhães S G, Chaves C M, Troper A 2011 Supercond. Sci. Technol. 24 035004
[31] Wang Y C, Lü J, Ma Y M, Cui T, Zou G T 2009 Phys. Rev. B 80 092505
[32] Lorenz B, Cmaidalka J, Meng R L, Chu C W 2003 Phys. Rev. B 68 014512
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