The ability to directly observe electronic band structure in modern nanoscale field-effect devices could transform understanding of their physics and function. One could, for example, visualize local changes in the electrical and chemical potentials as a gate voltage is applied. One could also study intriguing physical phenomena such as electrically induced topological transitions and many-body spectral reconstructions. Here we show that submicron angle-resolved photoemission (micro-ARPES) applied to two-dimensional (2D) van der Waals heterostructures affords this ability. In graphene devices, we observe a shift of the chemical potential by 0.6 eV across the Dirac point as a gate voltage is applied. In several 2D semiconductors we see the conduction band edge appear as electrons accumulate, establishing its energy and momentum, and observe significant band-gap renormalization at low densities. We also show that micro-ARPES and optical spectroscopy can be applied to a single device, allowing rigorous study of the relationship between gate-controlled electronic and excitonic properties.
@article{arxiv.1904.07301,
title = {Visualizing electrostatic gating effects in two-dimensional heterostructures},
author = {Paul V. Nguyen and Natalie C. Teutsch and Nathan P. Wilson and Joshua Kahn and Xue Xia and Viktor Kandyba and Alexei Barinov and Gabriel Constantinescu and Nicholas D. M. Hine and Xiaodong Xu and David H. Cobden and Neil R. Wilson},
journal= {arXiv preprint arXiv:1904.07301},
year = {2019}
}
Comments
Original manuscript with 9 pages with 4 figures in main text, 5 pages with 4 figures in supplement. Substantially edited manuscript accepted at Nature