Journal Article

Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2

Okuda, T., Di Sante, D., Vobornik, I., Bruyer, E., Picozzi, S., Ciancio, R., Panaccione, G., Fujii, J., Feldman, B. E., Yadzani, A., Ali, M. N., Rossi, G., Gyenis, A., Tao, J., Cava, R. J., Das, Pranab Kumar

2016

Overview

The behaviour of electrons and holes in a crystal lattice is a fundamental quantum phenomenon, accounting for a rich variety of material properties. Boosted by the remarkable electronic and physical properties of two-dimensional materials such as graphene and topological insulators, transition metal dichalcogenides have recently received renewed attention. In this context, the anomalous bulk properties of semimetallic WTe 2 have attracted considerable interest. Here we report angle- and spin-resolved photoemission spectroscopy of WTe 2 single crystals, through which we disentangle the role of W and Te atoms in the formation of the band structure and identify the interplay of charge, spin and orbital degrees of freedom. Supported by first-principles calculations and high-resolution surface topography, we reveal the existence of a layer-dependent behaviour. The balance of electron and hole states is found only when considering at least three Te–W–Te layers, showing that the behaviour of WTe 2 is not strictly two dimensional. Tungsten ditelluride is a semi-metallic two-dimensional material that has exhibited large magnetoresistance. Here, the authors use angle- and spin-resolved photoemission spectroscopy to investigate the band structure of this transition metal dichalcogenide and identify layer-dependent electronic behaviour.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 119/118 / 142/136 / 639/301/119/995 / 639/766/483/481 / 639/925 / CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY / Crystals / Humanities and Social Sciences / multidisciplinary / Physical properties / Science