[HiSOR x WPI-SKCM² Seminar] Keshav Shrestha (West Texas A & M University): Probing the Electronic Structure of Kagome Materials Using High-Field Torque Magnetometry

Abstract

Kagome materials, characterized by a lattice formed by corner-sharing triangles, provide a rich platform for exploring the interplay between lattice geometry, electronic structure, and emergent quantum phenomena. In this talk, I will first briefly overview our studies of the AV₃Sb₅ (A = K, Rb, Cs) family, focusing on superconductivity and charge-density-wave (CDW) order and how these phases can be tuned through chemical substitution and physical pressure [1, 2]. I will then focus on our recent work on the newly discovered kagome metal LuNb₆Sn₆, for which the Fermi-surface properties have remained largely unexplored. LuNb₆Sn₆ undergoes a CDW transition below 85 K. Using high-field torque magnetometry in fields up to 41 T and temperatures as low as 0.35 K, we observed clear de Haas–van Alphen (dHvA) oscillations with frequencies reaching 2500 T [3]. Detailed angle-dependent measurements were then performed to map the Fermi-surface geometry. Using first-principles calculations of both the pristine and CDW phases, I will show that the experimentally observed dHvA frequencies can be explained by reconstructed Fermi-surface pockets in the CDW phase.

References
[1] K. Shtefiienko et al., Phys. Rev. B 111, 235135 (2025).
[2] K. Shtefiienko et al., Phys. Rev. B 113, 035119 (2026).
[3] T. Beekmann et al., Phys. Rev. B, in press.

Zoom information

https://us02web.zoom.us/j/2022111100

(Meeting code: 2022111100 Password: skcm2)