First-principles study on the stability and electronic structure of monolayer GaSe with trigonal-antiprismatic structure

Open Access

First-principles study on the stability and electronic structure of monolayer GaSe with trigonal-antiprismatic structure

Hirokazu Nitta, Takahiro Yonezawa, Antoine Fleurence, Yukiko Yamada-Takamura, and Taisuke Ozaki

Phys. Rev. B 102, 235407 – Published 4 December 2020

Abstract

The structural stability and electronic states of GaSe monolayer with trigonal-antiprismatic (AP) structure, which is a recently discovered polymorph, were studied by first-principles calculations. The AP-phase GaSe monolayer was found stable, and the differences in energy and lattice constant were small when compared to those calculated for a GaSe monolayer with conventional trigonal-prismatic (P) structure which was found to be the ground state. Moreover, it was revealed that the relative stability of P-phase and AP-phase GaSe monolayers reverses under tensile strain. These calculation results provide insight into the formation mechanism of AP-phase GaSe monolayers in epitaxially grown GaSe thin films.

Received 4 June 2020
Revised 22 October 2020
Accepted 26 October 2020

DOI:https://doi.org/10.1103/PhysRevB.102.235407

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Atomic orbital Band gap Crystal symmetry Density functional theory First-principles calculations van Hove singularity

2-dimensional systems Chalcogenides

Atomic, Molecular & OpticalCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Hirokazu Nitta¹, Takahiro Yonezawa ¹, Antoine Fleurence ¹, Yukiko Yamada-Takamura¹, and Taisuke Ozaki²

¹School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
²Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan

Article Text

Click to Expand

Supplemental Material

Click to Expand

References

Click to Expand

Issue

Vol. 102, Iss. 23 — 15 December 2020

Reuse & Permissions

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
Top view (top), side view (middle), and perspective view (bottom) of crystal structures of (a) prismatic (P)-phase and (b) antiprismatic (AP)-phase GaSe monolayers. Blue thin lines highlight (a) the triangular prism and (b) antiprism. P phase has mirror symmetry [mirror plane in red in the perspective view of (a)] and no inversion symmetry, while AP phase has inversion symmetry [inversion center indicated as red point in the perspective view of (b)]. Images of structures were produced with vesta [47].
Reuse & Permissions
Figure 2
Energy vs lattice constant curves for P- and AP-phase monolayer GaSe. The lattice constants of the structurally optimized P-phase and AP-phase GaSe monolayers are 3.81 and 3.82 Å, respectively.
Reuse & Permissions
Figure 3
The transition of relative total energy per formula unit from P-phase (left) to AP-phase (right) monolayer GaSe by the NEB calculation at in-plane lattice constant of 3.81 Å. The energy barrier between both phases is 1.1 eV per formula unit. The top and side views of GaSe structure at selected distance from P-phase GaSe are presented. The energy difference between P-phase and AP-phase GaSe is 8 meV per formula unit.
Reuse & Permissions
Figure 4
Structural parameters as a function of the in-plane lattice constant for the P- and AP-phase monolayer GaSe. (a) Layer thickness, (b) Ga-Ga, and (c) Ga-Se bond. Layer thickness is the difference between the $c$ coordinates of Se atoms shown in the inset of (a). Black and red dashed lines are equilibrium in-plane lattice constants of P- and AP-phase GaSe, respectively. (d) Magnitude of displacement from the structure at the equilibrium in-plane lattice constant. Black and gray color indicate Ga and Se atoms, respectively, and the length of the arrows indicate the magnitude of displacements.
Reuse & Permissions
Figure 5
(a)–(c) Band structures, DOS, and PDOS for the P-phase GaSe monolayer with the equilibrium in-plane lattice constant. (d)–(f) Same for AP-phase GaSe monolayer at its equilibrium in-plane lattice constant. All were calculated without including SOC. Pseudoatomic orbital contribution is depicted on the band structures by the color and size of the circles.
Reuse & Permissions
Figure 6
Calculated band structures of P- and AP-phase monolayer GaSe at their respective equilibrium lattice constants. Bands near topmost valence band are shown, which are calculated without (solid line) and with (dashed line) SOC. Band structures (a), (b) along high-symmetry directions, and (c), (d) around Γ point, respectively.
Reuse & Permissions

Physical Review B

covering condensed matter and materials physics