Abstract
Kagome lattice is a fertile platform for topological and intertwined electronic excitations. Recently, experimental evidence of an unconventional charge density wave (CDW) is observed in a Z2 kagome metal AV3Sb5 (A=K, Cs, Rb). This observation triggers wide interest in the interplay between frustrated crystal structure and Fermi surface instabilities. Here, we analyze the lattice effect and its impact on CDW in AV3Sb5. Based on published experimental data, we show that the 2×2×2 CDW breaks the sixfold rotational symmetry of the crystal due to the phase shift between kagome layers and can explain the twofold symmetric CDW peak intensity observed by scanning tunneling spectroscopy. The coupling between the lattice and electronic degrees of freedom yields a weak first-order structural transition without continuous change of lattice dynamics. Our result emphasizes the fundamental role of lattice geometry in proper understanding of unconventional electronic orders in AV3Sb5.
Original language | English |
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Article number | 195132 |
Journal | Physical Review B |
Volume | 104 |
Issue number | 19 |
DOIs | |
State | Published - Nov 15 2021 |
Funding
We thank Kun Jiang for stimulating discussion on the interplay between CDW patterns and lattice distortions and Yimian Yang for technical support. This research was sponsored by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division and by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. H.C.L. was supported by National Key R&D Program of China (Grant No. 2018YFE0202600), National Natural Science Foundation of China (Grants No. 11822412 and No. 11774423), and Beijing Natural Science Foundation (Grant No. Z200005). Z.Q.W. is supported by the U.S. Department of Energy, Basic Energy Sciences Grant No. DE-FG02-99ER45747. B.Y. acknowledges the financial support by the European Research Council (ERC Consolidator Grant "NonlinearTopo", No. 815869), the ISF - Quantum Science and Technology (No. 1251/19). Work at Princeton University is supported by the US Department of Energy under the Basic Energy Sciences programme (Grant No. DOE/BES DE-FG-02-05ER46200).