Electronic and optical properties of α -InX (X = S, Se and Te) monolayer: Under strain conditions

Morbec

et al. 2018

Phys. Rev. Materials

First-principles calculations based on density-functional theory were performed to investigate heterostructures of group-III monochalcogenides (GaS, GaSe, InS and InSe) and the effects of the incommensurability on their electronic structures. We considered two heterostructures, GaS/GaSe, which has a lattice mismatch of 4.7%, and GaSe/InS, with a smaller mismatch of 2.1%, and we computed the cost of having commensurate structures; we also examined the potential energy landscape of both heterostructures, in order to simulate the realistic situation of incommensurate systems. We found that a commensurate heterostructure may be realized in GaSe/InS as the interaction energy of this system with the monolayers assuming the average lattice constant is smaller than the interaction energy of an incommensurate system in which each layer keeps its own lattice constant. For GaS/GaSe, on the other hand, we found that the incommensurate heterostructure is energetically more favorable than the commensurate one, even when taking into account the energetic cost due to the lack of proper registry between the layers. Since the commensurate condition requires that one (or both) layer(s) is (are) strained, we systematically investigated the effect of strain on the band gaps and band edge positions of the monolayer systems. We found that, in all monolayers, the conduction band minimum is more than 2 times more sensitive to applied strain than the valence band maximum; this was observed to strongly affect the band alignment of GaS/GaSe, as it can change from type-I to type-II with a small variation in the lattice constant of GaS. GaSe/InS heterostructure was found to have a type-II alignment, which is robust with respect to strain in the range of −2 to +2%.

Section: A Monolayer Gas Gase Ins and Insementioning

confidence: 99%

Commensurate versus incommensurate heterostructures of group-III monochalcogenides

Morbec

et al. 2018

Phys. Rev. Materials

“…Band c is the lowest energy conduction band, with its quadratic Γ-point dispersion described by an effectivemass single-band Hamiltonian, H c . The highest-energy occupied band, v, has a maximum offest from Γ in the monolayer [33][34][35][36]40,41,45 , and we therefore describe the band with a 4th order polynomial, H v . The next-highest energy valence bands, v 1 and v 2 , are dominated by p x , p y orbitals, and are twice-degenerate at Γ.…”

Section: Monolayermentioning

confidence: 99%

“…These experiments have identified two main photoluminescence lines, interpreted 30 as a lower energy transition between bands dominated by s and p z orbitals (A-line) and hot luminescence, involving holes in a deeper valence band based on p x and p y orbitals (B-line). The band structure analysis of mono-and few-layer InSe [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] has revealed that the conduction and valence band edges near the Γ-point are non-degenerate, being dominated by s and p z orbitals of both metal and chalcogen atoms. Combined with the opposite z → −z (mirror reflection) symmetry of conduction and valence bands, this determines that the transition across the principal band gap has a dominantly electric dipole-like character, coupled to out-of-plane polarized photons.…”

Section: Introductionmentioning

confidence: 99%

Spin-orbit coupling, optical transitions, and spin pumping in monolayer and few-layer InSe

2017

We show that spin-orbit coupling (SOC) in InSe enables the optical transition across the principal band gap to couple with in-plane polarized light. This transition, enabled by px,y ↔ pz hybridization due to intra-atomic SOC in both In and Se, can be viewed as a transition between two dominantly s-and pz-orbital based bands, accompanied by an electron spin-flip. Having parametrized k · p theory using first principles density functional theory we estimate the absorption for σ ± circularly polarized photons in the monolayer as ∼ 1.5%, which saturates to ∼ 0.3% in thicker films (3 − 5 layers). Circularly polarized light can be used to selectively excite electrons into spin-polarized states in the conduction band, which permits optical pumping of the spin polarization of In nuclei through the hyperfine interaction.

Physica E: Low-dimensional Systems and Nanostructures

“…Therefore, in this article, the main goal is the control of the electronic characteristics of InTe by exerting biaxial tensile and compressive strain by using first-principles calculations. This is shown that applying strain can move conduction band minimum (CBM) from M -point to Γ point 25 . Strain can decrease band-gap with a linear relation.…”

Section: Introductionmentioning

confidence: 99%

Electrical and electronic properties of strained mono-layer InTe

Touski

Ariapour

Hosseini

2020

In this paper, electrical and electronic properties of strained mono-layer InTe for two structures, α, and β phases, is investigated. The band structure is obtained using density functional theory (DFT). The minimum energy and effective mass of the conduction band and second conduction band for different strains are calculated. A FET with using InTe as the channel material is investigated. Voltage-current characteristics of InTe FET is calculated and ION /IOF F ratio is obtained with respect to biaxial strain.PACS numbers: