Related papers: Optical evidence of blue shift in topological insu…
Topological insulators possess a non-conductive bulk and present surface states, henceforth, they are electrically conductive along their boundaries. Bismuth selenide ($Bi_2Se_3$) is one of the most promising topological insulators.…
This work focuses on the low frequency Drude response of bulk-insulating topological insulator Bi$_2$Se$_3$ films. The frequency and field dependence of the mobility and carrier density are measured simultaneously via time-domain terahertz…
We report on the low-frequency current fluctuations and electronic noise in thin-films made of bismuth selenide topological insulators. The films were prepared via the graphene-like mechanical exfoliation and used as the current conducting…
At the ultra-thin film limit, quantum confinement strongly improves thermoelectric figure of merit in materials such as Sb$_2$Te$_3$ and Bi$_2$Te$_3$. These high quality films have only been realized using well controlled techniques such as…
Angle-resolved photoelectron spectroscopy is used for a detailed study of the electronic structure of the topological insulator Bi2Se3. Nominally stoichiometric and calcium-doped samples were investigated. The pristine surface shows the…
Infrared transparent conductors have long been sought due to their broad optoelectronic applications in the infrared wavelength range. However, the search for ideal materials has been limited by the inherent trade-off between electrical…
We report the experimental observation of Landau quantization of molecular beam epitaxy grown Sb2Te3 thin films by a low-temperature scanning tunneling microscope. Different from all the reported systems, the Landau quantization in Sb2Te3…
While two-dimensional topological insulators (2D TI) initiated the field of topological materials, only very few materials were discovered to date and the direct access to their quantum spin Hall edge states has been challenging due to…
The topological insulating phase results from inversion of the band gap due to spin-orbit coupling at an odd number of time-reversal symmetric points. In Bi$_2$Se$_3$, this inversion occurs at the $\Gamma$ point. For bulk Bi$_2$Se$_3$, we…
Few-layer InSe draws tremendous research interests owing to the superior electronic and optical properties. It exhibits high carrier mobility up to more than 1000 cm2/Vs at room temperature. The strongly layer-tunable band gap spans a large…
Understanding the superconducting proximity effect on the surface of a topological insulator is of critical importance in realizing topological superconductivity and Majorana fermions in solid state settings. We fabricate delicate…
Transient reflectivity measurements of thin films, ranging from 6 to 40 nm in thickness, of the topological insulator Bi2Se3 revealed a strong dependence of the carrier relaxation time on the film thickness. For thicker films the relaxation…
When surface states (SSs) form in topological insulators (TIs), they inherit the properties of bulk bands, including the electron-hole (e-h) asymmetry but with much more profound impacts. Here, via combining magneto-infrared spectroscopy…
Topological superconductor is a timely and frontier topic in condensed matter physics. In superconducting state, an order parameter will be established with the basic or subsidiary symmetry of the crystalline lattice. In doped Bi2Se3 with a…
Raman scattering [K. M. F. Shahil et al., Appl. Phys. Lett. 96, 153103 (2010), V. Gnezdilov et al., Phys. Rev. B 84, 195118 (2011) and H. H. Kung et al., Phys. Rev. B 95, 245406 (2017)], inelastic helium scattering [X. Zhu et al., Phys.…
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…
We report on fabrication of a two-dimensional topological insulator-Bi(111) bilayer on Sb nanofilms via a sequential molecular beam epitaxy (MBE) growth technique. Our angle-resolved photoemission measurements demonstrate the evolution of…
Combining the ability to prepare high-quality, intrinsic Bi$_2$Te$_3$ topological insulator thin films of low carrier density with in-situ protective capping, we demonstrate a pronounced, gate-tunable change in transport properties of…
Topological insulators represent a new state of quantum matter attractive to both fundamental physics and technological applications such as spintronics and quantum information processing. In a topological insulator, the bulk energy gap is…
We investigate the shift current bulk photovoltaic response of materials close to a band inversion topological phase transition. We find that the bulk photocurrent reverses direction across the band inversion transition, and that its…