The electronic structure of surface chains in the layered semiconductor In4Se3(100)

Abstract

The ordered (100) surface of layered In4Se3 single crystals is characterized by semiconducting quasi-one-dimensional indium (In) chains. A band with significant dispersion in the plane of the surface is observed near the valence band maximum. The band exhibits an anisotropic dispersion with ∼1eV band width along the In chain direction. The dispersion of this band is largely due to the hybridization of In-s and Se-p orbitals, but the hybridization between In-s and Se-p and In-p and Se-p orbitals is also critical in establishing the band gap.

Ab initiocalculations and ellipsometry measurements of the optical properties of the layered semiconductorIn4Se3

“…56͒ is also making progress in non-linear optical properties such as those shown under the incidence of "strong" laser beams 57 or ultrafast phenomena in semiconductors. 58 We have not used the scissors operator since our electronic structure calculations reproduce quite well the experimental band structure 12 and our band gap is comparable to those reported in the literature.…”

“…Based on our previous electronic structure results, 12,14 we discuss the location and nature of the main optical peaks appearing in the spectra. As a companion to the theory, we report the determination of the intrinsic orthorhombic optical properties for photon energies from 0.76 to 3.…”

“…3͔͒ and theoretical ͑e.g., lattice dynamics modelization, 10 pseudopotential band structure calculations 11 ͒ studies have been reported. In previous work, [12][13][14] we studied both the surface and the bulk electronic states, showing that the system does have a bulk band structure ͑i.e., discernable and significant band dispersion͒ perpendicular to the cleavage plane, 13 with an anisotropic dispersion of about 1 eV in the In chain direction. 12 In spite of all these known details of the band structure, to the best of our knowledge neither experimental data ͑with the exception of far-infrared optical properties [15][16][17] ͒ nor theoretical calculations of wide range optical spectra of the In 4 Se 3 are available in the literature.…”

“…In previous work, [12][13][14] we studied both the surface and the bulk electronic states, showing that the system does have a bulk band structure ͑i.e., discernable and significant band dispersion͒ perpendicular to the cleavage plane, 13 with an anisotropic dispersion of about 1 eV in the In chain direction. 12 In spite of all these known details of the band structure, to the best of our knowledge neither experimental data ͑with the exception of far-infrared optical properties [15][16][17] ͒ nor theoretical calculations of wide range optical spectra of the In 4 Se 3 are available in the literature. Therefore, and since state-of-the-art calculations have sensibly improved, an exhaustive and updated theoretical study of the In 4 Se 3 optical properties based on ab initio calculations is quite desirable.…”

Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides

“…In order to achieve high power factor, selective charge localization of electron or hole is essential because the electron-hole mixing gives rise to Seebeck coefficient compensation. As a candidate material of quasi 1D systems, In 4 Se 3 is very promising because it has natural nanowire-like cylindrical clusters and quasi-one-dimensional Indium chains at the cleavage (100) surface from the scanning tunneling microscopy (STM) measurements [16,17,18]. The In 4 Se 3 has a layered crystal structure of (In 3 ) 5+ clusters covalently bonded to Se ions in the bc -planes held together by van der Waals interactions along the a -axis.…”