Related papers: Ambipolar magneto-optical response of ultra-low ca…
Pb$_{1-x}$Sn$_x$Te has been shown to be an interesting tunable topological crystalline insulator system. We present a magneto-terahertz spectroscopic study of thin films of Pb$_{0.5}$Sn$_{0.5}$Te. The complex Faraday rotation angle and…
An important challenge in the field of topological materials is to carefully disentangle the electronic transport contribution of the topological surface states from that of the bulk. For Bi$_2$Te$_3$ topological insulator samples, bulk…
Topological insulators have been predicted to exhibit a variety of interesting phenomena including a quantized magnetoelectric response and novel spintronics effects due to spin textures on their surfaces. However, experimental observation…
When time-reversal symmetry is weakly broken and interactions are neglected, the surface of a $Z_{2}$ topological insulator supports a half-quantized Hall conductivity $\sigma_{S} = e^{2}/(2h)$. A surface Hall conductivity in an insulator…
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…
Ultrafast carrier dynamics in the topological insulator Bi2Se3 have recently been intensively studied using a variety of techniques. However, we are not aware of any successful experiments exploiting transient absorption (TA) spectroscopy…
The topological magneto-electric effect (TME) is a characteristic property of topological insulators. In this article, we use a simplified coupled-Dirac-cone electronic structure model to theoretically evaluate the THz and far infrared Kerr…
Magnetically doped topological insulators have been extensively studied over the past decade as a material platform to exhibit quantum anomalous Hall effect. Most material realizations are magnetically doped and despite material advances…
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…
We report the successful formation of bulk insulating ternary topological insulators candidate Bi2Se2Te (BST) by pulsed laser deposition technique. The films were deposited with sequential ablation of separate Bi2Se3 (BS) and Bi2Te3 (BT)…
We report transport studies on (Bi,Sb)2Te3 topological insulator thin films with tunable electronic band structure. We find a doping and temperature regime in which the Hall coefficient is negative indicative of electron-type carriers,…
Massless Dirac fermions occur as low-energy modes in several quasi-two-dimensional condensed matter systems such as graphene, the surface of bulk topological insulators, and in layered organic semiconductors. When the rotational symmetry in…
The great potential of Dirac electrons for plasmonics and photonics has been readily recognized after their discovery in graphene, followed by applications to smart optical devices. Dirac carriers are also found in topological insulators…
We present a theory for thin films of the Dirac semimetal Cd$_3$As$_2$ in the presence of magnetic fields. We show that, above a critical thickness, specific subbands $n$ of thin film Cd$_3$As$_2$ are in a quantum spin Hall insulator regime…
Starting from a three dimensional Hamiltonian, we study the optical properties of ultra-thin topological insulator slabs for which the coupling between Dirac fermions on opposite surfaces results in two degenerated gapped hyperbolic bands.…
(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…
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…
We investigate the optical properties of an ultrathin film of a topological insulator in the presence of an in-plane magnetic field. We show that due to the combination of the overlap between the surface states of the two layers and the…
Dirac fermions in condensed matter physics hold great promise for novel fundamental physics, quantum devices and data storage applications. IV-VI semiconductors, in the inverted regime, have been recently shown to exhibit massless…
We report on the effect of exposure to atmospheric conditions on the THz conductivity of thin films of the topological insulator Bi$_2$Se$_3$. We find: 1) two contributions of mobile charge carriers to the THz conductivity immediately after…