Pressure-induced stable structures and physical properties of Sr–Ge system  

作　　者：韩帅 段帅 刘云仙 王超 陈欣 孙海瑞 刘晓兵 Shuai Han;Shuai Duan;Yun-Xian Liu;Chao Wang;Xin Chen;Hai-Rui Sun;Xiao-Bing Liu(Laboratory of High Pressure Physics and Material Science,School of Physics and Physical Engineering,Qufu Normal University,Qufu 273165,China;Advanced Research Institute of Multidisciplinary Sciences,Qufu Normal University,Qufu 273165,China)

机构地区：[1]Laboratory of High Pressure Physics and Material Science,School of Physics and Physical Engineering,Qufu Normal University,Qufu 273165,China [2]Advanced Research Institute of Multidisciplinary Sciences,Qufu Normal University,Qufu 273165,China

出　　处：《Chinese Physics B》2023年第1期398-405,共8页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos.52102335,11704220,11804184,11974208,and 11804185);the Shandong Provincial Natural Science Foundation,China (Grant Nos.ZR2021MA050,ZR2017BA020,ZR2018PA010,ZR2019MA054,and ZR2017BA012)。

摘　　要：We have systematically investigated the structures of Sr-Ge system under pressures up to 200 GPa and found six stable stoichiometric structures,they being Sr_(3)Ge,Sr_(2)Ge,SrGe,SrGe_(2),SrGe_(3),and SrGe_(4).We demonstrate the interesting structure evolution behaviors in Sr-Ge system with the increase of germanium content,Ge atoms arranging into isolated anions in Sr_(3)Ge,chains in Sr_(2) Ge,square units in SrGe,trigonal units and hexahedrons in SrGe_(2),cages in SrGe_(3),hexagons and Geg rings in SrGe_(4).The structural diversity produces various manifestations of electronic structures,which is of benefit to electrical transportation.Among them,these novel phases with metallic structures show superconductivity(maximum T_(c)~8.94 K for Pmmn Sr_(3)Ge).Notably,the n-type semiconducting Pnma SrGe_(2) structure exhibits high Seebeck coefficient and excellent electrical conductivity along the y direction,leading to a high ZT value up to 1.55 at 500 K,which can be potential candidates as high-performance thermoelectrics.Our results will enable the development of fundamental science in condensed matter physics and potential applications in novel electronics or thermoelectric materials.

关 键 词：high pressure first-principle calculation germanium–strontium compounds SUPERCONDUCTIVITY thermoelectric property 

分 类 号：O469[理学—凝聚态物理]