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Title: Computational prediction of two-dimensional group-IV mono-chalcogenides

Density functional calculations determine the structure, stability, and electronic properties of two-dimensional materials in the family of group-IV monochalcogenides, MX (M = Ge, Sn, Pb; X = O, S, Se, Te). Calculations with a van der Waals functional show that the two-dimensional IV-VI compounds are most stable in either a highly distorted NaCl-type structure or a single-layer litharge type tetragonal structure. Their formation energies are comparable to single-layer MoS{sub 2}, indicating the ease of mechanical exfoliation from their layered bulk structures. The phonon spectra confirm their dynamical stability. Using the hybrid HSE06 functional, we find that these materials are semiconductors with bandgaps that are generally larger than for their bulk counterparts due to quantum confinement. The band edge alignments of monolayer group IV-VI materials reveal several type-I and type-II heterostructures, suited for optoelectronics and solar energy conversion.
Authors:
;  [1]
  1. Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States)
Publication Date:
OSTI Identifier:
22311363
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHALCOGENIDES; CONFINEMENT; CRYSTAL STRUCTURE; DENSITY FUNCTIONAL METHOD; ELECTRICAL PROPERTIES; FORECASTING; FORMATION HEAT; MOLYBDENUM SULFIDES; PHONONS; SEMICONDUCTOR MATERIALS; SODIUM CHLORIDES; SOLAR CELLS; SOLAR ENERGY CONVERSION; SPECTRA; STABILITY; TWO-DIMENSIONAL CALCULATIONS; VAN DER WAALS FORCES