Angle-resolved photoemission study and first-principles calculation of the electronic structure of GaTe

Abstract

The electronic band structure of GaTe has been calculated by numerical atomic orbitals densityfunctional theory, in the local density approximation. In addition, the valence-band dispersion along various directions of the GaTe Brillouin zone has been determined experimentally by angle-resolved photoelectron spectroscopy. Along these directions, the calculated valence-band structure is in good concordance with the valence-band dispersion obtained by these measurements. It has been established that GaTe is a direct-gap semiconductor with the band gap located at the Z point, that is, at Brillouin zone border in the direction perpendicular to the layers. The valence-band maximum shows a marked p-like behavior, with a pronounced anion contribution. The conduction band minimum arises from states with a comparable s-p-cation and p-anion orbital contribution. Spinorbit interaction appears to specially alter dispersion and binding energy of states of the topmost valence bands lying at Γ. By spin-orbit, it is favored hybridization of the topmost pz-valence band with deeper and flatter px-py bands and the valence-band minimum at Γ is raised towards the Fermi level since it appears to be determined by the shifted up px-py bands.

Ab initioguided optimization of GaTe for radiation detection applications

“…1, also reproduces the main features of the experimental data, including a direct band gap at the Z point of the BZ, as previously reported. 24 (Including spin-orbit effects does not significantly alter the band structure, as also previously reported, 25 so we neglect it here.) The calculated band gap is 0.68 eV, significantly below the experimental value of 1.8 eV, 4,9,24 as expected for LDA.…”

“…Defects on sites 2 were not explicitly calculated for most cases, since their characteristics are similar to sites 3. Figure 4 illustrates the qualitative electronic difference between site 1 and sites 2 and 3, for both Ga and Te sites, by showing the atomprojected local density of states at the band edges (Z point in the Brillouin zone 24 ). A clear distinction of site 1, with a small contribution to the formation of the band-edge states, and the similarity between sites 2 and 3 is apparent.…”

Second and third harmonic generation in few-layer gallium telluride characterized by multiphoton microscopy

“…GaTe is especially attractive as it has a direct bandgap of 1.65 eV. [14][15][16] In contrast to these studies, very little is known about the nonlinear optical properties of few-layer GaTe although they can play an important role in various photonic and optoelectronics applications. Nonlinear absorption properties for wavelengths shorter than 1064 nm have been reported 17 for bulk GaTe crystals.…”

Bandgap Restructuring of the Layered Semiconductor Gallium Telluride in Air

“…We begin with pristine GaTe followed by GaTe O 2 , GaTe H 2 O and GaTe OH. [32][33][34] The contribution of the orbitals to the partial density of states (PDOS) of GaTe can be seen in Figure S4a (Supporting Information). This value is still below the extrapolated 1.8 eV at 0 K [ 12 ] but is a better approximation than those reported elsewhere.…”