相关论文: Tuning Chemical Potential in the Dirac Cone by Com…
Topological insulators (TIs) are intriguing materials for advanced computing applications based on spintronics because they can host robust spin effects. For instance, TIs have intrinsically large spin generation enabled by their large…
We report that the ionic-liquid gating of bulk single crystals of a topological insulator can control the type of the surface carriers and even results in ambipolar transport. This was made possible by the use of a highly bulk-insulating…
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 (TIs) host unusual surface states with Dirac dispersion and helical spin texture and hold high potentials for novel applications in spintronics and quantum computing. Control of the chemical potential in these…
Uniform and large area synthesis of bulk insulating ultrathin films is an important subject toward applications of a surface of three dimensional topological insulators (3D-TIs) in various electronic devices. Here we report epitaxial growth…
Topological insulators (TIs) like Bi$_2$Se$_3$ are a class of material with topologically protected surface states in which spin-momentum locking may enable spin-polarized and defect-tolerant transport. In this work, we achieved the…
We measure the temperature-dependent carrier density and resistivity of the topological surface state of thin exfoliated Bi2Se3 in the absence of bulk conduction. When the gate-tuned chemical potential is near or below the Dirac point the…
In this work, we use charge extraction via organic overlayer deposition to lower the chemical potential of topological insulator Bi2Se3 thin films into the intrinsic (bulk-insulating) regime. We demonstrate the tuning and stabilization of…
We have designed three-dimensional models of topological insulator thin films, showing a tunability of the odd number of Dirac cones on opposite surfaces driven by the atomic-scale geometry at the boundaries. This enables creation of a…
Transient reflectivity (TR) from thin films (6 - 40 nm thick) of the topological insulator Bi2Se3 reveal ultrafast carrier dynamics, which suggest the existence of both radiative and non-radiative recombination between electrons residing in…
Thermoelectric (TE) devices have been attracting increasing attention because of their ability to convert heat directly to electricity. To date, improving the TE figure of merit remains the key challenge. The advent of the topological…
In this study, high-quality thin films of the topological semimetal phase NiTe$_2$ were prepared using molecular beam epitaxy (MBE) technique, confirmed through X-ray diffraction with pronounced Laue oscillations. Electrical transport…
The massless Dirac fermions residing on the surface of three-dimensional topological insulators are protected from backscattering and cannot be localized by disorder, but such protection can be lifted in ultrathin films when the…
Topological insulators are novel quantum materials with metallic surface transport, but insulating bulk behavior. Often, topological insulators are dominated by bulk contributions due to defect induced bulk carriers, making it difficult to…
(Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ alloys are non-degenerate topological insulators (TIs) whose Dirac point (DP) can be tuned within the bulk bandgap by varying the composition, effectively reducing bulk conduction while allowing surface carrier…
This paper reviews recent developments in quantum transport and it presents recent efforts to explore the contribution of topological insulator boundary states to thermoelectricity in Bi$_2$Te$_3$ thin films. Although Bi$_2$Te$_3$ has been…
We have investigated the THz range magneto-optical response of ultralow carrier density films of Sb$_2$Te$_3$ using time-domain THz polarimetry. Undoped Sb$_2$Te$_3$ has a chemical potential that lies inside the bulk valence band. Thus its…
Band structure engineering and interfacial buffer layers have been demonstrated as effective means to tune the Fermi level in topological insulators (TI). In particular, the charge compensated compound (BixSb1-x)2Te3 (BST) plays a critical…
We discuss the magnetic and topological properties of bulk crystals and quasi-two-dimensional thin films formed by stacking intrinsic magnetized topological insulator ( for example Mn(Sb$_{x}$Bi$_{1-x}$)$_2$X$_4$ with X = Se,Te, including…
We demonstrate the ability to reduce the carrier concentration of thin films of the topological insulator (TI) Bi2Se3 by utilizing a novel approach, namely non-volatile electrostatic gating via corona charging of electret polymers.…