A first-principles Quantum Monte Carlo study of two-dimensional (2D) GaSe

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dc.contributor.authorWines, Daniel
dc.contributor.authorSaritas, Kayahan
dc.contributor.authorAtaca, Can
dc.date.accessioned2020-11-25T16:31:44Z
dc.date.available2020-11-25T16:31:44Z
dc.date.issued2020-10-19
dc.description.abstractTwo-dimensional (2D) post-transition metal chalcogenides (PTMCs) have attracted attention due to their suitable bandgaps and lower exciton binding energies, making them more appropriate for electronic, optical, and water-splitting devices than graphene and monolayer transition metal dichalcogenides. Of the predicted 2D PTMCs, GaSe has been reliably synthesized and experimentally characterized. Despite this fact, quantities such as lattice parameters and band character vary significantly depending on which density functional theory (DFT) functional is used. Although many-body perturbation theory (GW approximation) has been used to correct the electronic structure and obtain the excited state properties of 2D GaSe, and solving the Bethe–Salpeter equation (BSE) has been used to find the optical gap, we find that the results depend strongly on the starting wavefunction. In an attempt to correct these discrepancies, we employed the many-body Diffusion Monte Carlo (DMC) method to calculate the ground and excited state properties of GaSe because DMC has a weaker dependence on the trial wavefunction. We benchmark these results with available experimental data, DFT [local-density approximation, Perdew-Burke-Ernzerhof (PBE), strongly constrained and appropriately normed (SCAN) meta-GGA, and hybrid (HSE06) functionals] and GW-BSE (using PBE and SCAN wavefunctions) results. Our findings confirm that monolayer GaSe is an indirect gap semiconductor (Γ-M) with a quasiparticle electronic gap in close agreement with experiment and low exciton binding energy. We also benchmark the optimal lattice parameter, cohesive energy, and ground state charge density with DMC and various DFT methods. We aim to present a terminal theoretical benchmark for pristine monolayer GaSe, which will aid in the further study of 2D PTMCs using DMC methods.en_US
dc.description.sponsorshipThis work was supported by the National Science Foundation through the Division of Materials Research under Grant No. NSF DMR-1726213.en_US
dc.description.urihttps://aip.scitation.org/doi/10.1063/5.0023223en_US
dc.format.extent11 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m2euli-xtdf
dc.identifier.citationDaniel Wines, Kayahan Saritas and Can Ataca, A first-principles Quantum Monte Carlo study of two-dimensional (2D) GaSe, J. Chem. Phys. 153, 154704 (2020); https://doi.org/10.1063/5.0023223en_US
dc.identifier.urihttps://doi.org/10.1063/5.0023223
dc.identifier.urihttp://hdl.handle.net/11603/20138
dc.language.isoen_USen_US
dc.publisherAIP publishingen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Physics Department Collection
dc.relation.ispartofUMBC Faculty Collection
dc.relation.ispartofUMBC Student Collection
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
dc.rightsThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Daniel Wines, Kayahan Saritas and Can Ataca, A first-principles Quantum Monte Carlo study of two-dimensional (2D) GaSe, J. Chem. Phys. 153, 154704 (2020); https://doi.org/10.1063/5.0023223 and may be found at https://doi.org/10.1063/5.0023223
dc.rightsAccess to this item will begin on 10/19/2021
dc.titleA first-principles Quantum Monte Carlo study of two-dimensional (2D) GaSeen_US
dc.typeTexten_US

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