型烧绿石氧化物超导体AOs2O6 (A=K, Rb) 的声子软化与超导电性

孙家法; 王玮

doi:10.7498/aps.61.137402

摘要

运用基于密度泛函理论的第一性原理计算方法, 研究两种型烧绿石氧化物超导体AOs2O6(A=K, Rb) 的结构稳定性, 声子软化以及与超导电性的关系. 通过计算发现, AOs2O6中碱金属原子A(=K, Rb) 沿〈111〉晶向具有不稳定性, 且以K原子的不稳定性更为突出. 同时, 计算得到的KOs2O6在布里渊区中心的声子频率普遍比RbOs2O6的低, 使得KOs2O6的电声子耦合常数比RbOs2O6的大. 本文计算结果表明, 较小的碱金属原子K位于较大的氧笼子中, 活动性较强, 导致声子的软化, 是引起KOs2O6具有较强的电声子耦合及较高的超导转变温度的根本原因. 这些结果对解释两种型烧绿石氧化物超导体AOs2O6(A=K, Rb) 的超导电性具有重要意义.

关键词:

Abstract

Using the first-principles calculational method based on the density functional theory, we study the structural instabilities, phonon softenings, and their relation to the superconductivities of two -pyrochlore oxide superconductors AOs2O6(A=K, Rb). It is found that there are structural instabilities of alkali ions along the 〈111〉 direction in the two -pyrochlore oxide superconductors AOs2O6(A=K, Rb), especially in KOs2O6. Meanwhile, a comparison of the phonon frequency at zone-center between KOs2O6 and RbOs2O6 shows that the frequency of KOs2O6 is lower in general than that of RbOs2O6, leading to the stronger electron-phonon coupling. We conclude that K atom located in a large oxygen cage has an unusual large atomic displacement parameter and strong activity, thereby resulting in strong phonon softening. This is the foundamental cause for stronger electron-phonon coupling and higher superconducting transition temperature of KOs2O6. These are of significance for explaining the superconductivities in -pyrochlore oxide superconductors AOs2O6(A=K, Rb).

Keywords:

作者及机构信息

孙家法¹,
王玮²

1.
淮北师范大学信息学院, 淮北 235000;

2.
淮北师范大学物理与电子信息学院, 淮北 235000

基金项目: 国家自然科学基金青年科学基金(批准号: 11104100)和淮北师范大学青年科研项目(批准号: 700429) 资助的课题.

Authors and contacts

Sun Jia-Fa¹,
Wang Wei²

1.
Information College of Huaibei Normal University, Anhui 235000, China;

2.
School of Physics and Electronic Information, Huaibei Normal University, Anhui 235000, China

Funds: Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11104100), and Youth Scientific Research Fund of Huaibei Normal University of China (Grant No. 700429).

参考文献

[1]	Yonezawa S, Muraoka Y, Matsushita Y, Hiroi Z 2004 J. Phys: Condens Matter 16 L9-L12
[2]	Yonezawa S, Muraoka Y, Matsushita Y, Hiroi Z 2004 J. Phys. Soc. Jpn. 73 819
[3]
[4]
[5]	Yamaura J, Yonezawa S, Muraoka Y Hiroi Z 2006 J. Solid State Chem. 179 336
[6]
[7]	Hiroi Z, Yonezawa S, Nagao Y, Yamaura J 2007 Phys. Rev. B 76 014523
[8]
[9]	Brhwiler M, Kazakov S M, Karpinski J, Batlogg B 2006 Phys. Rev. B 73 094518
[10]
[11]	Yoshida M, Arai K, Kaido R, Takigawa M, Yonezawa S, Muraoka Y, Hiroi Z 2007 Phys. Rev. Lett. 98 197002
[12]
[13]	Hasegawa T, Takasu Y, Ogita N, Udagawa M 2007 Phys. Rev. B 77 064303
[14]
[15]	Wang W, Sun J F, Liu M, Liu S 2009 Acta Phys. Sin. 58 5632 (in Chinese) [王玮, 孙家法, 刘楣, 刘甦 2009 物理学报 58 5632]
[16]	Xin X G, Chen X, Zhou J J, Shi S Q 2011 Acta Phys. Sin. 60 028201 (in Chinese) [忻晓桂, 陈香, 周晶晶, 施思齐 2011 物理学报 60 028201]
[17]
[18]
[19]	Blaha P, Schwarz K 2003 Comp. Mater. Sci. 28 259
[20]	Wu Z, Cohen R E 2006 Phys. Rev. B 73 235116
[21]
[22]
[23]	Baroni S, de Gironcoli S, Dal Corso A, Giannozzi P, Avalibale from http: //www.pwscf.org
[24]	Vanderbilt D 1990 Phys. Rev. B 41 7892
[25]
[26]
[27]	Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865
[28]	Kendziora C A, Sergienko I A, Jin R, He J, Keppens V, Sales B C, Mandrus D 2005 Phys. Rev. Lett. 95 125503
[29]
[30]	Sergienko I A, Curnoe S H 2003 J. Phys. Soc. Jpn. 72 1607
[31]
[32]
[33]	Yamaura J, Hiroi Z 2002 J. Phys. Soc. Jpn. 71 2598
[34]	An J M, Pickett W E 2001 Phys. Rev. Lett. 86 4366
[35]
[36]
[37]	Huang G Q, Chen L F, Liu M, Xing D Y 2004 Phys. Rev. B 69 064509
[38]	Ma R, Huang G Q, Liu M 2007 Acta Phys. Sin. 56 4960 (in Chinese) [马荣, 黄桂芹, 刘楣 2007 物理学报 56 4960]
[39]
[40]	Zhang J H, Ma R, Liu S, Liu M 2006 Acta Phys. Sin. 55 4816 (in Chinese) [张加宏, 马荣, 刘甦, 刘楣 2006 物理学报 55 4816]
[41]
[42]	Ttnc H M, Srivastava G P 2006 J. Phys: Condens Matter 18 11089
[43]
[44]	Li B, Xing Z W, Liu M 2011 Acta Phys. Sin. 60 077402 (in Chinese) [李斌, 邢钟文, 刘楣 2011 物理学报 60 077402]
[45]
[46]	Wang W, Sun J F, Li S W, Lu H Y 2012 Physica C 472 29
[47]

施引文献

[1]	Yonezawa S, Muraoka Y, Matsushita Y, Hiroi Z 2004 J. Phys: Condens Matter 16 L9-L12
[2]	Yonezawa S, Muraoka Y, Matsushita Y, Hiroi Z 2004 J. Phys. Soc. Jpn. 73 819
[3]
[4]
[5]	Yamaura J, Yonezawa S, Muraoka Y Hiroi Z 2006 J. Solid State Chem. 179 336
[6]
[7]	Hiroi Z, Yonezawa S, Nagao Y, Yamaura J 2007 Phys. Rev. B 76 014523
[8]
[9]	Brhwiler M, Kazakov S M, Karpinski J, Batlogg B 2006 Phys. Rev. B 73 094518
[10]
[11]	Yoshida M, Arai K, Kaido R, Takigawa M, Yonezawa S, Muraoka Y, Hiroi Z 2007 Phys. Rev. Lett. 98 197002
[12]
[13]	Hasegawa T, Takasu Y, Ogita N, Udagawa M 2007 Phys. Rev. B 77 064303
[14]
[15]	Wang W, Sun J F, Liu M, Liu S 2009 Acta Phys. Sin. 58 5632 (in Chinese) [王玮, 孙家法, 刘楣, 刘甦 2009 物理学报 58 5632]
[16]	Xin X G, Chen X, Zhou J J, Shi S Q 2011 Acta Phys. Sin. 60 028201 (in Chinese) [忻晓桂, 陈香, 周晶晶, 施思齐 2011 物理学报 60 028201]
[17]
[18]
[19]	Blaha P, Schwarz K 2003 Comp. Mater. Sci. 28 259
[20]	Wu Z, Cohen R E 2006 Phys. Rev. B 73 235116
[21]
[22]
[23]	Baroni S, de Gironcoli S, Dal Corso A, Giannozzi P, Avalibale from http: //www.pwscf.org
[24]	Vanderbilt D 1990 Phys. Rev. B 41 7892
[25]
[26]
[27]	Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865
[28]	Kendziora C A, Sergienko I A, Jin R, He J, Keppens V, Sales B C, Mandrus D 2005 Phys. Rev. Lett. 95 125503
[29]
[30]	Sergienko I A, Curnoe S H 2003 J. Phys. Soc. Jpn. 72 1607
[31]
[32]
[33]	Yamaura J, Hiroi Z 2002 J. Phys. Soc. Jpn. 71 2598
[34]	An J M, Pickett W E 2001 Phys. Rev. Lett. 86 4366
[35]
[36]
[37]	Huang G Q, Chen L F, Liu M, Xing D Y 2004 Phys. Rev. B 69 064509
[38]	Ma R, Huang G Q, Liu M 2007 Acta Phys. Sin. 56 4960 (in Chinese) [马荣, 黄桂芹, 刘楣 2007 物理学报 56 4960]
[39]
[40]	Zhang J H, Ma R, Liu S, Liu M 2006 Acta Phys. Sin. 55 4816 (in Chinese) [张加宏, 马荣, 刘甦, 刘楣 2006 物理学报 55 4816]
[41]
[42]	Ttnc H M, Srivastava G P 2006 J. Phys: Condens Matter 18 11089
[43]
[44]	Li B, Xing Z W, Liu M 2011 Acta Phys. Sin. 60 077402 (in Chinese) [李斌, 邢钟文, 刘楣 2011 物理学报 60 077402]
[45]
[46]	Wang W, Sun J F, Li S W, Lu H Y 2012 Physica C 472 29
[47]

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