Powered by Indico
v3.2.3
Kagome materials, characterized by their two-dimensional corner-sharing triangular sublattices, exhibit distinctive electronic structures, including flat bands, von Hove singularities (vHS), and Dirac points, resulting from their unique crystalline architecture. The divergent density of states (DOS) associated with flat bands and vHS in these materials is a promising avenue for exploring various instabilities. The recent discovery of the charge density wave (CDW) in the kagome metals AV3Sb5 (A=K, Rb, Cs) has sparked significant interest. Utilizing first-principles calculations, we have identified the inverse star-of-David configuration as the fundamental CDW structure in AV3Sb5, highlighting the pivotal role of vHS in CDW genesis[1]. This structure aligns with numerous experimental observations and lays the groundwork for further theoretical exploration[2]. Contrastingly, in the newly discovered kagome metal ScV6Sn6, vHS plays a minor role in CDW formation, possibilly attributed to its minimal presence in the Brillouin zone and resultant weak Fermi surface nesting[3]. Here, the CDW is primarily driven by electron-phonon coupling. We have predicted varying CDW orders in ScV6Sn6, subsequently confirmed experimentally. While the CDW in AV3Sb5 predominantly involves in-plane vibrations of the kagome sublattice, in ScV6Sn6, it is characterized by the out-of-plane oscillations of non-kagome atoms, leaving the kagome sublattice unaffected. These contrasting CDW characteristics in AV3Sb5 and ScV6Sn6 offer a unique platform for investigating the interplay of charge, phonon, spin, and other interactions, potentially shedding light on the enigmatic CDW phenomena in the magnetic kagome metal.
[1] H. Tan et al. Charge Density Waves and Electronic Properties of Superconducting Kagome Metals, Phys. Rev. Lett. 127, 046401 (2021).
[2] H. Tan et al. Emergent topological quantum orbits in the charge density wave phase of kagome metal CsV3Sb5, npj Quantum Mater. 8, 39 (2023).
[3] H. Tan et al. Abundant Lattice Instability in Kagome Metal ScV6Sn6. Phy. Rev. Lett. 130, 266402 (2023)
Hengxin Tan graduated with a Bachelor's degree in Applied Physics from Dalian University of Technology in 2013, and then joined Professor Wenhui Duan's research group at Tsinghua University, where he earned his Ph.D. in Condensed Matter Physics in January 2019. Following his doctorate, Hengxin embarked on postdoctoral research with Professor Stuart Parkin's group at the Max-Planck Institute for Microstructure Physics in Halle (Saale), Germany. Since the summer of 2020, he moved to the Weizmann Institute of Science in Israel, working with Prof. Binghai Yan. During his Ph.D., his research focused on the theoretical aspects of ferroelectrics/multiferroics and transition metal oxides. His postdoctoral work is centered on theoretical studies of topological quantum materials. His current research is primarily devoted to elucidating and predicting novel properties in kagome materials. He has published more than 40 papers with three first-author Phys. Rev. Lett. papers and earned 1300 citations.
Tencent meeting link: https://meeting.tencent.com/dm/1DcVYW29fhON Meeting ID: 710 842 099