Indexed by: Journal paper

First Author: Yueshan Xu

Correspondence Author: Zhi-Guo Chen

Co-author: Jianlin Luo,Youguo Shi,Hechang Lei,Alexey A. Soluyanov,Ling Lu,Gang Xu,Enke Liu,Luyang Wang,Xiaolei Hu,Yilin Wang,Qiangwei Yin,Qi Wang,Changjiang Yi,Jianzhou Zhao

Journal: Nature Communications

Included Journals: SCI

Discipline: Science

First-Level Discipline: Physics

Document Type: J

Volume: 11

Issue: 1

Page Number: 3985

ISSN No.: 2041-1723

Date of Publication: 2020-08-10

Impact Factor: 14.919

Abstract: The interplay between electronic correlations and topological protection may offer a rich avenue for discovering emergent quantum phenomena in condensed matter. However, electronic correlations have so far been little investigated in Weyl semimetals (WSMs) by experiments. Here, we report a combined optical spectroscopy and theoretical calculation study on the strength and effect of electronic correlations in a magnet Co3Sn2S2. The electronic kinetic energy estimated from our optical data is about half of that obtained from single-particle ab initio calculations in the ferromagnetic ground state, which indicates intermediate-strength electronic correlations in this system. Furthermore, comparing the energy and side-slope ratios between the interband-transition peaks at high energies in the experimental and single-particle-calculation-derived optical conductivity spectra with the bandwidth-renormalization factors obtained by many-body calculations enables us to estimate the Coulomb-interaction strength (U ∼ 4 eV) in Co3Sn2S2. Besides, a sharp experimental optical conductivity peak at low energy, which is absent in the single-particle-calculation-derived spectrum but is consistent with the optical conductivity peaks obtained by many-body calculations with U ∼ 4 eV, indicates that an electronic band connecting the two Weyl cones is flattened by electronic correlations and emerges near the Fermi energy in Co3Sn2S2. Our work paves the way for exploring flat-band-generated quantum phenomena in WSMs.