Band structure and optical transitions in atomic layers of hexagonal gallium chalcogenides

By V. Zólyomi, N. Drummond, Vladimir Fal'ko. 2013

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We report density-functional-theory calculations of the electronic band structures and optical absorption spectra of two-dimensional crystals of Ga2X2 (X= S, Se, and Te). Our calculations show that all three two-dimensional materials are dynamically stable indirect-band-gap semiconductors with a sombrero dispersion of holes near the top of the valence band. We predict the existence of Lifshitz transitions—changes in the Fermi-surface topology of hole-doped Ga2X2—at hole concentrations nS=7.96×1013 cm−2, nSe=6.13×1013 cm−2, and nTe=3.54×1013 cm−2.

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/9740dd0a825886260fb15cff2bd367fda8123fcf