Evidence for reduced periodic lattice distortion within the Sb-terminated surface layer of the kagome metal CsV3Sb5

Abstract

The discovery of the kagome metal CsV3Sb5 sparked broad interest, due to the coexistence of a charge density wave (CDW) phase and possible unconventional superconductivity in the material. In this Letter, we use low-energy electron diffraction (LEED) with a μm-sized electron beam to explore the periodic lattice distortion at the antimony-terminated surface in the CDW phase. We recorded high-quality backscattering diffraction patterns in ultrahigh vacuum from multiple cleaved samples. Unexpectedly, we did not find superstructure reflexes at intensity levels predicted from dynamical LEED calculations for the reported 2×2×2 bulk structure. Our results suggest that in CsV3Sb5 the periodic lattice distortion accompanying the CDW is less pronounced at Sb-terminated surfaces than in the bulk.