Topological hourglass Dirac semimetal in Ag2BiO3

ORAL

Abstract

Materials with tunable charge and lattice degrees of freedom provide excellent platforms for investigating multiple phases that can be controlled via external stimuli. We show how the charge-ordered ferroelectric oxide Ag2BiO3, which has been realized experimentally, presents a unique exemplar of a metal-insulator transition under an external electric field. Our first-principles calculations combined with a symmetry analysis, reveal the presence of a nearly ideal hourglass-Dirac-semimetal state in the nonpolar structure of Ag2BiO3. The low-energy band structure consists of two hourglass-like nodal lines located on two mutually orthogonal glide-mirror planes in the absence of spin-orbit coupling (SOC) effects. These lines cross at a common point and form an interlinked chain-like structure, which extends beyond the first Brillouin zone. Inclusion of the SOC opens a small gap in the nodal lines and results in two symmetry-enforced hourglass-like Dirac points on the C2y screw rotation axis. Our results indicate that Ag2BiO3 will provide an ideal platform for exploring ferroelectric-semiconductor to Dirac-semimetal transition by the application of an external electric field.

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Presenters

  • Bahadur Singh

    SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D, Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA /SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for, Department of Physics, National University of Singapore, SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science \& Technology, Engineering Technology Research Center for 2, Department of Physics, Northeastern University, Shenzhen University, Shenzhen, China, College of Optoelectronic Engineering, Shenzhen University

Authors

  • Bahadur Singh

    SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D, Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA /SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for, Department of Physics, National University of Singapore, SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science \& Technology, Engineering Technology Research Center for 2, Department of Physics, Northeastern University, Shenzhen University, Shenzhen, China, College of Optoelectronic Engineering, Shenzhen University

  • Barun Ghosh

    Physics, Indian Institute of Technology Kanpur,Kanpur 208016, India, Indian Institute of Technology Kanpur, India

  • Chenliang Su

    SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D, SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science \& Technology, Engineering Technology Research Center for 2, Shenzhen University, Shenzhen, China, SZU-NUS Collaborative Center and International Collaborative, Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2

  • Hsin Lin

    Academia Sinica, Institute of Physics, Academia Sinica, Physics, Academia Sinica, Taipei 11529, Taiwan, Institute of Physics, Academia Sinica, Taipei 11529, Taiwan, Physics, Academia Sinica, Department of Physics, National University of Singapore, National University of Singapore, Academia Sinica, Taipei, Taiwan

  • Amit Agarwal

    Physics, Indian Institute of Technology Kanpur,Kanpur 208016, India, Indian Institute of Technology Kanpur, India

  • Arun Bansil

    Department of Physics, Northeastern University, Northeastern, Physics, Northeastern University, Boston, Massachusetts 02115, USA, Northeastern University, Northeastern University, Boston (MA), USA, Physics, Northeastern U., Department of Physics, Northwestern University, Physics, Northeastern University, Boston, MA, USA