Coexistence of Superconductivity and Superhardness in Beryllium Hexaboride Driven by Inherent Multicenter Bonding

被引：23

作者：

Wu, Lailei ^{[1
]}

Wan, Biao ^{[1
,2
]}

Liu, Hanyu ^{[3
]}

Gou, Huiyang ^{[2
,4
]}

Yao, Yansun ^{[5
,6
]}

Li, Zhiping ^{[4
]}

Zhang, Jingwu ^{[1
]}

Gao, Faming ^{[4
]}

Mao, Ho-kwang ^{[2
,3
]}

机构：

[1] Yanshan Univ, Coll Mat Sci & Engn, Key Lab Metastable Mat Sci & Technol, Qinhuangdao 066004, Peoples R China

[2] Ctr High Pressure Sci & Technol Adv Res, Beijing 100094, Peoples R China

[3] Carnegie Inst Sci, Geophys Lab, 5251 Broad Branch Rd NW, Washington, DC 20015 USA

[4] Yanshan Univ, Coll Environm & Chem Engn, Key Lab Appl Chem, Qinhuangdao 066004, Peoples R China

[5] Univ Saskatchewan, Dept Phys & Engn Phys, Saskatoon, SK S7N 5E2, Canada

[6] Canadian Light Source, Saskatoon, SK S7N 2V3, Canada

来源：

JOURNAL OF PHYSICAL CHEMISTRY LETTERS | 2016年 / 7卷 / 23期

基金：

中国国家自然科学基金; 加拿大自然科学与工程研究理事会; 中国博士后科学基金;

关键词：

AB-INITIO; PHONON-DISPERSION; BORON; HARDNESS; PHASE; IRON;

D O I：

10.1021/acs.jpclett.6b02444

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Unique multicenter bonding in boron -rich materials leads to the formation of complex structures and intriguing properties. Here global structural searches are performed to unearth the structure of beryllium hexaboride (BeB6) synthesized decades ago. Three BeB6 phases (alpha,beta and gamma) were predicted to be stable at ambient and high pressures. The ground state at ambient pressure, alpha-BeB6, consists of a strong and uniformly distributed covalent B-B network, which results in exceptional elastic properties and a hardness of 46 GPa comparable to gamma-B. Even more surprisingly, alpha-BeB6 retains credible electron phonon coupling in the boron sublattice, and is predicted to be superconducting at 9 K. Above 4 GPa, beta-BeB6 is stabilized with alternating boron slabs and triangular beryllium layers analogous to the structure of MgB2. The beta-BeB6 is predicted to be superconducting at 24 K, similar to Nb-3(AI,Ge). The gamma-BeB6 is stable above 340 GPa. The understanding of intrinsic multicenter-bonding mechanism and related properties demonstrated in the very example of BeB6 provides new insights for the design of tunable multifunctional materials.

引用

页码：4898 / 4904

页数：7