Related papers: Optical conductivity of Bismuth-based topological …
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…
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…
Using Terahertz Time-Domain Spectroscopy, we study the temperature-dependent complex optical conductivity of the topological insulator, Bi$_{1.5}$Sb$_{0.5}$Te$_{1.8}$Se$_{1.2}$ single-crystal from 5 K to 150 K in the terahertz regime (0.4…
Three-dimensional topological insulators harbour metallic surface states with exotic properties. In transport or optics, these properties are typically masked by defect-induced bulk carriers. Compensation of donors and acceptors reduces the…
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…
The optical conductivity and the spectral weight W(T) of two superconducting cuprates at optimum doping, Bi2Sr2-xLaxCuO6 and Bi2Sr2CaCu2O8, have been first measured up to 500 K. Above 300 K, W(T) deviates from the usual T2 behavior in both…
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…
Compensation of intrinsic charges is widely used to reduce the bulk conductivity of 3D topological insulators (TIs). Here we use low temperature electron irradiation-induced defects paired with in-situ electrical transport measurements to…
We study the optical response of a strongly correlated electron system near the metal-insulator transition using a mapping to the sine-Gordon model. With semiclassical quantization, the spectral weight is distributed between a Drude peak…
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…
A Bi2Se3 topological insulator field effect transistor is investigated by using ionic liquid as an electric double layer gating material, leading to a conductance modulation of 365% at room temperature. We discuss the role of charged…
The archetypical 3D topological insulators Bi2Se3, Bi2Te3 and Sb2Te3 commonly exhibit high bulk conductivities, hindering the characterization of the surface state charge transport. The optimally doped topological insulators Bi2Te2Se and…
We measure gate-tuned thermoelectric power of mechanically exfoliated Bi2Se3 thin films in the topological insulator regime. The sign of the thermoelectric power changes across the charge neutrality point as the majority carrier type…
The in-plane infrared and visible (3 meV-3 eV) reflectivity of Bi2Sr2CaCu2O8+d (Bi-2212) thin films is measured between 300 K and 10 K for different doping levels with unprecedented accuracy. The optical conductivity is derived through an…
Strontium intercalation between van der Waals bonded layers of topological insulator Bi2Se3 is found to induce superconductivity with a maximum Tc of 2.9 K. Transport measurement on single crystal of optimally doped sample Sr0.1Bi2Se3 shows…
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…
Topological insulators possess completely different spin-orbit coupled bulk and surface electronic spectra that are each predicted to exhibit exotic responses to light. Here we report time-resolved fundamental and second harmonic optical…
Topological insulators (TIs) are a class of materials characterized by an insulting bulk and high mobility topologically protected surface states, making them promising candidates for future optoelectronic and quantum devices. Although…
The optical conductivity for the surface excitations for a Topological Insulator as a function of the chemical potential and disorder is considered. Due to the time reversal symmetry the chiral metallic surface states are protected against…
Thin (6-7 quintuple layer) topological insulator Bi2Se3 quantum dot devices are demonstrated using ultrathin (2~4 quintuple layer) Bi2Se3 regions to realize semiconducting barriers which may be tuned from Ohmic to tunneling conduction via…