Electronic and optical properties of two-dimensional InSe from a DFT-parameterized tight-binding model

Abstract

We present a tight-binding (TB) model and $\mathbf{k}\cdot \mathbf{p}$ theory for electrons in monolayer and few-layer InSe. The model is constructed from a basis of all $s$ and $p$ valence orbitals on both indium and selenium atoms, with tight-binding parameters obtained from fitting to independently computed density functional theory (DFT) band structures for mono- and bilayer InSe. For the valence and conduction band edges of few-layer InSe, which appear to be in the vicinity of the $\Gamma$ point, we calculate the absorption coefficient for the principal optical transitions as a function of the number of layers, $N$. We find a strong dependence on $N$ of the principal optical transition energies, selection rules, and optical oscillation strengths, in agreement with recent observations \cite{Bandurin2016}. Also, we find that the conduction band electrons are relatively light ($m\propto 0.14-0.18m_e$), in contrast to an almost flat, and slightly inverted, dispersion of valence band holes near the $\Gamma$-point, which is found for up to $N\propto 6$.

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• Two Dimensional Atomic Crystals
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• Strong light-matter coupling in two-dimensional atomic crystals
• Hunting for Monolayer Boron Nitride: Optical and Raman Signatures
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Tunable Magnetism and Half-Metallicity in Hole-doped Monolayer GaSe
• Electrons and phonons in single layers of hexagonal indium chalcogenides from ab initio calculations

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• Spin-orbit coupling, optical transitions, and spin pumping in mono- and few-layer InSe
• Visualizing Orbital Content of Electronic Bands in Anisotropic 2D Semiconducting ReSe${}_2$
• Evidence of Direct Electronic Band Gap in two-dimensional van der Waals Indium Selenide crystals
• Tunable spin-orbit coupling in two-dimensional InSe
• Structures of bulk hexagonal post-transition-metal chalcogenides from dispersion-corrected density-functional theory
• Flat-band-induced many-body interactions and exciton complexes in a layered semiconductor
• Moiré-induced bandgap tuning by varying electric dipole in InSe/CuSe vertical heterostructure