Optical manipulation of Rashba-split 2-dimensional electron gas

Abstract

In spintronics, the two main approaches to actively control the electrons’ spin involve static magnetic or electric fields. An alternative avenue relies on the use of optical fields to generate spin currents, which can bolster spin-device performance, allowing for faster and more efficient logic. To date, research has mainly focused on the optical injection of spin currents through the photogalvanic effect, and little is known about the direct optical control of the intrinsic spin-splitting. To explore the optical manipulation of a material’s spin properties, we consider the Rashba effect. Using time- and angle-resolved photoemission spectroscopy (TR-ARPES), we demonstrate that an optical excitation can tune the Rashba-induced spin splitting of a two-dimensional electron gas at the surface of Bi2Se3. We establish that light-induced photovoltage and charge carrier redistribution - which in concert modulate the Rashba spin-orbit coupling strength on a sub-picosecond timescale - can offer an unprecedented platform for achieving optically-driven spin logic devices.

Enhanced sensing performance of armchair stanene nanoribbons for lung cancer early detection using an electric field

“…39 When a perpendicular external electric field is applied to electrons moving in a 2D material, the Rashba effect has to be taken into account and the term related to the Rashba effect should be added to the Hamiltonian. The Rashba energy term is described as follows 39,40 :…”

“…39 When a perpendicular external electric field is applied to electrons moving in a 2D material, the Rashba effect has to be taken into account and the term related to the Rashba effect should be added to the Hamiltonian. The Rashba energy term is described as follows 39,40 : H R = α R ( σ × k ) z where σ is the Pauli matrix, k is the electron wave vector, and α R is the Rashba parameter which is calculated as , e is the electron charge, z = 3 a 0 , a 0 is the Bohr radius, ξ is the strength of atomic spin–orbit interaction that is ξ = 0.8 eV, and V spσ = 2.65 eV is the nearest neighbor hopping parameter between s and p orbitals. E z is the strength of the external electric field perpendicular to the surface of a 2D material.…”

Scrutinizing a superconductor-topological insulator interface as a platform for topological superconductivity

“…In general, in the TI/SC heterostructure a TSS will appear on the free side at the interface between TI and vacuum, and also as a contact TSS at the interface between the TI and the SC which can hybridize with the states from the SC. Chemically, the SC/TI interface is a metalsemiconductor contact where charge transfer and band bending effects can lead to the occupation of trivial interface states in the accumulation region [23,24]. Our work discusses these different states that appear at the SC/TI contact and uncovers the interplay of wave function localization, superconducting proximity effect which may allow to further optimize the SC/TI interface using elemental SCs in the future.…”

Optoelectronic insights of lead-free layered halide perovskites

“…2d). [31][32][33] The coupling between electric eld, and the spin degrees of freedom is the basis of engineering the spintronic devices such as spin transistors, spin valves, and spin-based memory devices. 34 The Rashba effect can affect the carrier recombination pathways, through the creation of an indirect band gap whose magnitude depends on SOC, and the degree of symmetry breaking.…”