Emergent Edge Modes in Shifted Quasi-One-Dimensional Charge Density Waves

Song-Bo Zhang; Xiaoxiong Liu; Md Shafayat Hossain; Jia-Xin Yin; M Zahid Hasan; Titus Neupert

doi:10.1103/PhysRevLett.130.106203

Emergent Edge Modes in Shifted Quasi-One-Dimensional Charge Density Waves

Phys Rev Lett. 2023 Mar 10;130(10):106203. doi: 10.1103/PhysRevLett.130.106203.

Authors

Song-Bo Zhang¹, Xiaoxiong Liu¹, Md Shafayat Hossain², Jia-Xin Yin³, M Zahid Hasan^{2

4

5

6}, Titus Neupert¹

Affiliations

¹ Department of Physics, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
² Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08540, USA.
³ Department of physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
⁴ Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, USA.
⁵ Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁶ Quantum Science Center, Oak Ridge, Tennessee 37831, USA.

PMID: 36962034
DOI: 10.1103/PhysRevLett.130.106203

Abstract

We propose and study a two-dimensional phase of shifted charge density waves (CDW), which is constructed from an array of weakly coupled 1D CDW wires whose phases shift from one wire to the next. We show that the fully gapped bulk CDW has topological properties, characterized by a nonzero Chern number, that imply edge modes within the bulk gap. Remarkably, these edge modes exhibit spectral pseudoflow as a function of position along the edge, and are thus dual to the chiral edge modes of Chern insulators with their spectral flow in momentum space. Furthermore, we show that the CDW edge modes are stable against interwire coupling. Our predictions can be tested experimentally in quasi-1D CDW compounds such as Ta_{2}Se_{8}I.