title: First-principles study on the structural and electronic properties of metallic HfH2 under pressure.
abstract: The crystal structures and properties of hafnium hydride under pressure are explored using the first-principles calculations based on density function theory. The material undergoes pressure-induced structural phase transition I4/mmm → Cmma → P21/m at 180 and 250 GPa, respectively, and all of these structures are metallic. The superconducting critical temperature Tc values of I4/mmm, Cmma, and P21/m are 47-193 mK, 5.99-8.16 K and 10.62-12.8 K at 1 atm, 180 and 260 GPa, respectively. Furthermore, the bonding nature of HfH2 is investigated with the help of the electron localization function, the difference charge density and Bader charge analyses, which show that HfH2 is classified as a ionic crystal with the charges transferring from Hf atom to H.
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Yunxian
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Defang
authors.initials: D
authors.lastname: Duan
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Fubo
authors.initials: F
authors.lastname: Tian
authors.affiliation: Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Canada, S7N 5E2.
authors.forename: Hanyu
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Da
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Zhonglong
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Sha
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Huadi
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Tian
authors.initials: T
authors.lastname: Cui