Related papers: Control over topological insulator photocurrents w…
Topological insulators constitute a new and fascinating class of matter with insulating bulk yet metallic surfaces that host highly mobile charge carriers with spin-momentum locking. Remarkably, the direction and magnitude of surface…
In recent years, a class of solid state materials, called three-dimensional topological insulators, has emerged. In the bulk, a topological insulator behaves like an ordinary insulator with a band gap. At the surface, conducting gapless…
Topological insulators are characterized by Dirac cone surface states with electron spins aligned in the surface plane and perpendicular to their momenta. Recent theoretical and experimental work implied that this specific spin texture…
One of the most striking manifestations of electronic properties of topological insulators is the dependence of the photocurrent direction on the helicity of circularly polarized optical excitation. The helicity dependent photocurrents,…
We study the photocurrent response of topological insulator surface states to circularly polarized light for arbitrary oblique incidence. We describe the surface states within a Dirac model, including several perturbations such as hexagonal…
Circular photogalvanic currents are a promising new approach for spin-optoelectronics. To date, such currents have only been induced in topological insulator flakes or extended films. It is not clear whether they can be generated in…
Optical control of helicity-dependent photocurrent in topological insulator Sb$_2$Te$_2$Se has been studied at room temperature on dominantly c-axis oriented granular polycrystalline samples grown by pulsed laser deposition technique.…
Three-dimensional topological insulators are a class of Dirac materials, wherein strong spin-orbit coupling leads to two-dimensional surface states. The latter feature spin-momentum locking, i.e., each momentum vector is associated with a…
We report on time-resolved ultrafast optical spectroscopy study of the topological insulator (TI) Bi$_2$Se$_3$. We unravel that a net spin polarization can not only be generated using circularly polarized light via interband transitions…
Recently discovered materials called three-dimensional topological insulators constitute examples of symmetry protected topological states in the absence of applied magnetic fields and cryogenic temperatures. A hallmark characteristic of…
Topological insulators represent a new quantum state of matter that are insulating in the bulk but metallic on the edge or surface. In the Dirac surface state, it is well-established that the electron spin is locked with the crystal…
We study the microscopic origins of photocurrent generation in the topological insulator Bi$_2$Se$_3$ via time- and angle-resolved photoemission spectroscopy. We image the unoccupied band structure as it evolves following a circularly…
Recently, a new quantum phase, the topological insulator, has been vividly investigated in a variety of materials. Its unique bandstructure allows for optical generation and control of spin-polarized currents based on the circular…
Circularly polarized photons are known to generate a directional helicity-dependent photocurrent in three-dimensional topological insulators at room temperature. Surprisingly, the phenomenon is readily observed at photon energies that…
We introduce a dinstint approach to engineer a topologically protected surface state of a topological insulator. By covering the surface of a topological insulator, Bi2Te2Se, with a Bi monolayer film, the original surface state is…
Topological insulators are a new phase of matter that exhibits exotic surface electronic properties. Determining the spin texture of this class of material is of paramount importance for both fundamental understanding of its topological…
Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topological order. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators…
The recently discovered topological insulators exhibit topologically protected metallic surface states which are interesting from the fundamental point of view and could be useful for various applications if an appropriate electronic gating…
Three dimensional (3D) topological insulators are quantum materials with a spin-orbit induced bulk insulating gap that exhibit quantum-Hall-like phenomena in the absence of applied magnetic fields. The proposed applications of topological…
Despite the broadband response, limited optical absorption at a particular wavelength hinders the development of optoelectronics based on Dirac fermions. Heterostructures of graphene and various semiconductors have been explored for this…