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arXiv · 2412.02813

Real-Space Imaging of the Band Topology of Transition Metal Dichalcogenides

Madisen Holbrook·Julian Ingham·Daniel Kaplan·Luke Holtzman·Brenna Bierman·Nicholas Olson·Luca Nashabeh·Song Liu·Xiaoyang Zhu·Daniel Rhodes·Katayun Barmak·James Hone·Raquel Queiroz·Abhay Pasupathy
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Abstract

The topological properties of Bloch bands are intimately tied to the structure of their electronic wavefunctions within the unit cell of a crystal. Here, we show that scanning tunneling microscopy (STM) measurements on the prototypical transition metal dichalcogenide (TMD) semiconductor WSe$_2$ can be used to unambiguously fix the location of the Wannier center of the valence band. Using site-specific substitutional doping, we first determine the position of the atomic sites within STM images, establishing that the maximum electronic density of states at the $K$-point lies between the atoms. In contrast, the maximum density of states at the $\Gamma$ point is at the atomic sites. This signifies that WSe$_2$ is a topologically obstructed atomic insulator, which cannot be adiabatically transformed to the trivial atomic insulator limit.

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Madisen Holbrook, Julian Ingham, Daniel Kaplan, Luke Holtzman, Brenna Bierman, Nicholas Olson, Luca Nashabeh, Song Liu, Xiaoyang Zhu, Daniel Rhodes, Katayun Barmak, James Hone, Raquel Queiroz, Abhay Pasupathy. 2024-12-03. Real-Space Imaging of the Band Topology of Transition Metal Dichalcogenides. https://arxiv.org/abs/2412.02813

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