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arXiv · 2407.03768

Two-dimensional to bulk crossover of the WSe$_2$ electronic band structure

Patrick Le Fèvre·Raphaël Salazar·Matthieu Jamet·François Bertran·Chiara Bigi·Abdelkarim Ourghi·Céline Vergnaud·Aki Pulkkinen·Jan Minar·Thomas Jaouen·Julien Rault
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Abstract

Transition Metal Dichalcogenides (TMD) are layered materials obtained by stacking two-dimensional sheets weakly bonded by van der Waals interactions. In bulk TMD, band dispersions are observed in the direction normal to the sheet plane (z-direction) due to the hybridization of out-of-plane orbitals but no kz-dispersion is expected at the single-layer limit. Using angle-resolved photoemission spectroscopy, we precisely address the two-dimensional to three-dimensional crossover of the electronic band structure of epitaxial WSe$_2$ thin films. Increasing number of discrete electronic states appears in given kz-ranges while increasing the number of layers. The continuous bulk dispersion is nearly retrieved for 6-sheet films. These results are reproduced by calculations going from a relatively simple tight-binding model to a sophisticated KKR-Green's function calculation. This two-dimensional system is hence used as a benchmark to compare different theoretical approaches.

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Patrick Le Fèvre, Raphaël Salazar, Matthieu Jamet, François Bertran, Chiara Bigi, Abdelkarim Ourghi, Céline Vergnaud, Aki Pulkkinen, Jan Minar, Thomas Jaouen, Julien Rault. 2024-07-04. Two-dimensional to bulk crossover of the WSe$_2$ electronic band structure. https://arxiv.org/abs/2407.03768

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