Topological insulators-based magnetic heterostructures

Abstract

The combination of magnetism and topology in magnetic topological insulators (MTIs) has led to unprecedented advancements of time reversal symmetry-breaking topological quantum physics in the past decade. Compared with the uniform films, the MTI heterostructures provide a better framework to manipulate the spin-orbit coupling and magnetic/spin properties. In this review, we summarize the fundamental mechanisms related to the physical orders host in (Bi,Sb) 2 (Te,Se) 3 -based hybrid systems. Besides, we provide an assessment on the general strategies to enhance the magnetic coupling and spin-orbit torque strength through different structural engineering approaches and effective interfacial interactions. Finally, we offer an outlook of MTI heterostructures-based spintronics applications, particularly in view of their feasibility to achieve room-temperature operation.

Controlling the spin current around the rectangular cavities in two-dimensional topological insulators

“…The two types of magnetic defects, including Ising symmetry ( J z S a 0 and J AE S = 0) and xy symmetry ( J z S = 0 and J AE S a 0), enable different patterns of spin-polarized currents. 46,52,53 The formalism of bond current allows for the computation of physically measurable spatial profiles of local current within the TIs in the non-equilibrium condition. The spin-resolved bond current is calculated using the equations-of-motion approach for nonequilibrium Green's functions 54…”

“…The two types of magnetic defects, including Ising symmetry ( J z S ≠ 0 and J ± S = 0) and xy symmetry ( J z S = 0 and J ± S ≠ 0), enable different patterns of spin-polarized currents. 46,52,53…”

“…Besides, the presence of structural defects is found to have a critical influence on the overall magnetic behaviors in the TIs with exchange magnetic fields. 46,47 Motivated by the preceding studies, we will provide an example of the formation of localized and tunable spin-polarized currents around interior cavities in the TIs to prepare highly integrated TI-based spintronic devices.…”

Bottomonium suppression and flow in heavy-ion collisions

“…Instead one typically has πT ∼ m D and the relevant hierarchy of scales is 1/a 0 πT, m D E, where a 0 is the Bohr radius. In this case it can be shown that the quantum evolution is Markovian, with the local medium relaxation time being shorter than both the time scale associated with internal transitions and the probe (heavy quarkonium) relaxation time [5][6][7]. As a consequence, the dynamical equation which governs the evolution of the heavy quarkonium reduced density matrix is of Lindblad form [1,2].…”