Polarity-dependent charge-density wave in a kagome superconductor CsV3Sb5

Takemi Kato; Yongkai Li; Kosuke Nakayama; Zhiwei Wang; Seigo Souma; Miho Kitamura; Koji Horiba; Hiroshi Kumigashira; Takashi Takahashi; Takafumi Sato

doi:10.1103/physrevb.106.l121112

arXiv · 2209.14556

Polarity-dependent charge-density wave in a kagome superconductor CsV3Sb5

Takemi Kato·Yongkai Li·Kosuke Nakayama·Zhiwei Wang·Seigo Souma·Miho Kitamura·Koji Horiba·Hiroshi Kumigashira·Takashi Takahashi·Takafumi Sato

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Abstract

Polar surface and interface play a pivotal role for realizing exotic properties of materials, and a search for such polar states is of crucial importance for expanding materials' functionality. Here we report micro-focused angle-resolved photoemission spectroscopy of CsV3Sb5, a member of recently discovered kagome superconductors AV3Sb5 (A = K, Rb, Cs), and show evidence for the polar nature of cleaved surface which is characterized by Cs- and Sb-terminated surfaces with markedly different fermiology. The Cs-terminated surface shows intriguing doubling of V-derived bands at low temperature associated with the band folding due to the three-dimensional charge-density wave (CDW), whereas the Sb-terminated one shows no band doubling or resultant CDW-gap opening indicative of the suppression of bulk-originated CDW due to polar charge. Such polar-surface-dependent band structure must be incorporated for understanding the origin of unconventional superconducting and charge order at the surface of AV3Sb5.

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Takemi Kato, Yongkai Li, Kosuke Nakayama, Zhiwei Wang, Seigo Souma, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Takashi Takahashi, Takafumi Sato. 2022-09-29. Polarity-dependent charge-density wave in a kagome superconductor CsV3Sb5. https://doi.org/10.1103/physrevb.106.l121112

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