2013/02/28 by Viktor Zólyomi, V. Zólyomi, N. D. Drummond +2 · 223 citations
Chemistry · Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced Thermoelectric Materials and Devices #Band gap #Chalcogenide Semiconductor Thin Films #Chemistry #Computational chemistry #Condensed matter physics #Crystallography #Density functional theory #Direct and indirect band gaps #Doping #Electronic band structure #Electronic structure #Fermi level #Gallium #Hexagonal crystal system #Materials science #Optoelectronics #Physics #Quantum mechanics #Semiconductor #Semimetal #Valence (chemistry) #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.87.195403
published in Physical Review B 87(19) (American Physical Society)
arxiv created 2013/04/16 · openalex publication_date 2013/05/02 · arxiv updated 2018/01/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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\ifmmode×\else\texttimes\fi1013 cm^\ensuremath-2, nSe=6.13\ifmmode×\else\texttimes\fi1013 cm^\ensuremath-2, and nTe=3.54\ifmmode×\else\texttimes\fi1013 cm^\ensuremath-2.