相关论文: Interband absorption edge in topological insulator…

Using angle-resolved photoelectron spectroscopy and ab-initio GW calculations, we unambiguously show that the widely investigated three-dimensional topological insulator Bi2Se3 has a direct band gap at the Gamma point. Experimentally, this…

The temperature dependence of the complex optical properties of the three-dimensional topological insulator Bi2Te2Se is reported for light polarized in the a-b planes at ambient pressure, as well as the effects of pressure at room…

We performed broadband optical transmission measurements of Bi2Se3 and In-doped Bi(1-x)In(x)2Se3 thin films, where in the latter the spin-orbit coupling (SOC) strength can be tuned by introducing In. Drude and interband transitions exhibit…

We have investigated the band structure at the $\Gamma$ point of the three-dimensional (3D) topological insulator Bi$_2$Se$_3$ using magneto-spectroscopy over a wide range of energies ($0.55-2.2$\,eV) and in ultrahigh magnetic fields up to…

Bi2Se3 is a prototypical topological insulator which has a small band gap (~0.3 eV) and topologically protected conducting surface states. This material exhibits quite strong thermoelectric effects. Here we show in a mechanically exfoliated…

In$_2$Se$_3$ in the three-dimensional (3D) hexagonal crystal structure with space group $P6_1$ ($\gamma$-In$_2$Se$_3$) has a direct band gap of $\sim$1.8 eV and high absorption coefficient, making it a promising semiconductor material for…

We present an infrared magneto-optical study of the highly thermoelectric narrow-gap semiconductor Bi$_2$Se$_3$. Far-infrared and mid-infrared (IR) reflectance and transmission measurements have been performed in magnetic fields oriented…

Optical band gap properties of high-quality few-layer topological insulator Bi2Se3 thin films grown with magnetron sputtering are investigated using broadband absorption spectroscopy. We provide direct optical evidence of a rigid blue-shift…

The surface band bending tunes considerably the surface band structures and transport properties in topological insulators. We present a direct measurement of the band bending on the Bi2Se3 by using the bulk sensitive angular-resolved hard…

Three-dimensional (3-D) topological insulators (TI) are characterized by the presence of metallic surface states and a bulk band gap. Recently theoretical and experimental studies have shown an induced gap in the surface state bands of TI…

Topological insulators in the Bi2Se3 family have an energy gap in the bulk and a gapless surface state consisting of a single Dirac cone. Low frequency optical absorption due to the surface state is universally determined by the fine…

Here we report on Landau level spectroscopy of an epitaxially grown thin film of the topological insulator Sb2Te3, complemented by ellipsometry and magneto-transport measurements. The observed response suggests that Sb2Te3 is a direct-gap…

Here we report on Landau level spectroscopy in magnetic fields up to 34 T performed on a thin film of topological insulator Bi$_2$Te$_3$ epitaxially grown on a BaF$_2$ substrate. The observed response is consistent with the picture of a…

We have performed angle-resolved photoemission spectroscopy on (PbSe)5(Bi2Se3)3m, which forms a natural multilayer heterostructure consisting of a topological insulator (TI) and an ordinary insulator. For m = 2, we observed a gapped…

We use scanning tunneling microscopy and spectroscopy under ultra-high vacuum and down to 1.7 K to study the local variations of the chemical potential on the surface of the topological insulator (Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ thin films…

Bismuth selenide (Bi2Se3) is a prototypical three-dimensional topological insulator whose Dirac surface states have been extensively studied theoretically and experimentally. Surprisingly little, however, is known about the energetics and…

A topological insulator possesses a bulk energy gap splitting the lowest empty band from the highest occupied electronic band. The electronic states at the surface (or edge in two dimensions), on the other hand, of a topological insulator…

Two-dimensional materials with layered structures, appropriate bandgap, and high carrier mobilities have gathered tremendous interests due to their potential applications in optoelectronic and photovoltaic devices. Here, we report the…

Band structure and optical properties of defect- Chalcopyrite type semiconductor ZnIn$_2$Te$_4$ have been studied by TB-LMTO first principle technique. The optical absorption calculation suggest that ZnIn$_2$Te$_4$ is a direct-gap…

Bi$_{2}$Te$_{3}$ and Bi$_{2}$Se$_{3}$ are well known 3D-topological insulators. Films made of these materials exhibit metal-like surface states with a Dirac dispersion and possess high mobility. The high mobility metal-like surface states…