Phase Diagram and High-Temperature Superconductivity of Compressed Selenium Hydrides.
Recent discovery of high-temperature superconductivity (Tc = 190 K) in sulfur hydrides at megabar pressures breaks the traditional belief on the Tc limit of 40 K for conventional superconductors, and opens up the doors in searching new high-temperature superconductors in compounds made up of light elements. Selenium is a sister and isoelectronic element of sulfur, with a larger atomic core and a weaker electronegativity. Whether selenium hydrides share similar high-temperature superconductivity remains elusive, but it is a subject of considerable interest. First-principles swarm structure predictions are performed in an effort to seek for energetically stable and metallic selenium hydrides at high pressures. We find the phase diagram of selenium hydrides is rather different from its sulfur analogy, which is indicated by the emergence of new phases and the change of relative stabilities. Three stable and metallic species with stoichiometries of HSe2, HSe and H3Se are identified above ~120 GPa and they all exhibit superconductive behaviors, of which the hydrogen-rich HSe and H3Se phases show high Tc in the range of 40-110 K. Our simulations established the high-temperature superconductive nature of selenium hydrides and provided useful route for experimental verification.
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Shoutao
S
Zhang
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Yanchao
Y
Wang
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Jurong
J
Zhang
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Hanyu
H
Liu
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Xin
X
Zhong
LCP, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China.|Software Center for High Performance Numerical Simulation, China Academy of Engineering Physics, Beijing 100088, China.
Hai-Feng
HF
Song
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.|Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.
Guochun
G
Yang
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.|College of Materials Science and Engineering and Key Laboratory of Automobile Materials of MOE, Jilin University, Changchun 130012, China.
Lijun
L
Zhang
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Yanming
Y
Ma