Tuning the Electronic Structure of a 2 D

Tuning the Electronic Structure of a 2 D Material Scientific Achievement The electronic structure of a stacked 2 D material was tuned by in situ electron doping, resulting in a large increase in the splitting of two valence bands. Significance and Impact Stacked 2 D materials possess an array of tunable properties that are expected to be important for future applications in electronics and optics. Research Details − Single-layer tungsten disulfide (WS 2) was stacked on a thin flake of hexagonal boron nitride (h-BN). − The WS 2 was probed using microfocused angleresolved photoemission spectroscopy (micro. ARPES). − Electron doping increased WS 2 valence-band splitting from 430 to 660 me. V, driven by trions: three-particle combinations of electrons and holes. Atomic structure of WS 2 (blue/yellow) on h-BN (silver/gold) and WS 2 conduction (pink) and valence (green/blue) bands. A trion of 2 holes and 1 electron (red circles) is depicted in the valence and conduction bands. Background shows raw WS 2 electronic-structure data. (Credit: Chris Jozwiak, Berkeley Lab) Publication about this research: J. Katoch, S. Ulstrup, R. J. Koch, S. Moser, K. M. Mc. Creary, S. Singh, J. Xu, B. T. Jonker, R. K. Kawakami, A. Bostwick, E. Rotenberg, and C. Jozwiak, Nat. Phys. , doi: 10. 1038/s 41567 -017 -0033 -4 (2018). Work was performed at Lawrence Berkeley National Laboratory, ALS Beamline 7. 0. 2. Operation of the ALS is supported by the U. S. Department of Energy, Office of Science, Basic Energy Sciences program.