Electron-phonon coupling and symmetry breaking in the CDW phase of Kagome metals

by Dr Dirk Wulferding (Seoul National University)

Wednesday 10 May 2023, 10:00 → 11:00 Asia/Shanghai

ONLINE

Abstract

Metallic systems with flat electronic bands and Dirac points have recently gathered immense attention, as they are prone to numerous exotic and topological electronic phases and related instabilities. Particularly, the discovery of superconductivity in the layered metallic kagome compounds AV₃Sb₅ (A=Cs,K,Rb) has ignited a massive research effort to elucidate the nature and the pairing mechanism of this potential topological superconductor [1,2]. Of special relevance may be a neighboring charge-density-wave (CDW) phase – yet, its true role in establishing superconductivity in AV₃Sb₅ remains unresolved until now. We present a temperature and polarization resolved Raman scattering study on CsV3Sb5 single crystals [3]. Our highly angular-resolved Raman data sheds a light on the symmetry of CDW-related excitations and on selected phonons, which allude to an emergent C2 symmetry within the CDW phase. This symmetry-breaking together with phonon anomalies at T_CDW signify the formation of a nematic phase through a concerted interplay of electronic correlations and electron-phonon coupling within the exotic CDW phase.

[1] Ortiz, et al., Phys. Rev. Mater. 3, 094407 (2019).

[2] Ortiz, et al., Phys. Rev. Lett. 125, 247002 (2020).

[3] Wulferding, et al., Phys. Rev. Res. 4, 023215 (2022).

Biography

Dirk Wulferding holds a Senior Researcher position at Seoul National University (Korea). He got a PhD in 2013 in the group of Prof. Peter Lemmens at the Physics Department of Braunschweig University of Technology (Germany). From 2013-2017 he was a post-doctoral researcher at POSTECH (Korea), working in the group of Prof. Jeehoon Kim, before returning to Braunschweig for a Junior Group Leader position at the newly established Laboratory for Emergent Nanometrology. In 2020 he was awarded a Young Scientist Fellowship by the Institute of Basic Science and is subsequently working at the IBS-Center for Correlated Electron Systems in Seoul. He is a member of the American, German, and Korean Physical Society, and an author of more than 60 publications.

Division

Condensed Matter

Other information

Join Zoom Meeting
https://cern.zoom.us/j/63361602206?pwd=OWlPZEVTU3dRUUoxdlJWS0F0bEVDUT09

Meeting ID: 633 6160 2206
Passcode: 123456