title: Electronic Topological Transition in Ag2Te at High-pressure.
abstract: Recently, Ag2Te was experimentally confirmed to be a 3D topological insulator (TI) at ambient pressure. However, the high-pressure behaviors and properties of Ag2Te were rarely reported. Here, a pressure-induced electronic topological transition (ETT) is firstly found in Ag2Te at 1.8 GPa. Before ETT, the positive pressure coefficient of bulk band-gap, which is firstly found in TIs family, is found by both first-principle calculations and in situ high-pressure resistivity measurements. The electrical resistivity obtained at room temperature shows a maximum at 1.8 GPa, which is nearly 3.3 times to that at ambient pressure. This result indicates that the best bulk insulating character and topological nature in Ag2Te can be obtained at this pressure. Furthermore, the high-pressure structural behavior of Ag2Te has been investigated by in situ high-pressure synchrotron powder X-ray diffraction technique up to 33.0 GPa. The accurate pressure-induced phase transition sequence is firstly determined as P21/c → Cmca → Pnma. It is worth noting that the reported isostructural P21/c phase is not existed, and the reported structure of Cmca phase is corrected by CALYPSO methodology. The second high-pressure structure, a long puzzle to previous reports, is determined as Pnma phase. A pressure-induced metallization in Ag2Te is confirmed by the results of temperature-dependent resistivity measurements.
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Yuhang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Li
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Xuecheng
authors.initials: X
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
authors.forename: Pinwen
authors.initials: P
authors.lastname: Zhu