title: Transition between strong and weak topological insulator in ZrTe5and HfTe5.
abstract: ZrTe5and HfTe5have attracted increasingly attention recently since the theoretical prediction of being topological insulators (TIs). However, subsequent works show many contradictions about their topolog-ical nature. Three possible phases, i.e. strong TI, weak TI, and Dirac semi-metal, have been observed in different experiments until now. Essentially whether ZrTe5or HfTe5has a band gap or not is still a question. Here, we present detailed first-principles calculations on the electronic and topological prop-erties of ZrTe5and HfTe5on variant volumes and clearly demonstrate the topological phase transition from a strong TI, going through an intermediate Dirac semi-metal state, then to a weak TI when the crystal expands. Our work might give a unified explain about the divergent experimental results and propose the crucial clue to further experiments to elucidate the topological nature of these materials.
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Zongjian
authors.initials: Z
authors.lastname: Fan
authors.affiliation: Department of Physics, Shaoxing University, Shaoxing 312000, China.
authors.forename: Qi-Feng
authors.initials: QF
authors.lastname: Liang
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Y B
authors.initials: YB
authors.lastname: Chen
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Yao
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou