Wave-vector-dependent tunneling through magnetic barriers

Abstract

Near tunneling structures are proposed consisting of magnetic barriers that can be created by lithographic patterning of ferromagnetic or superconducting Slms. The form of the equivalent potential for such a barrier depends on the vive vector of the incident electron. This renders the transmission through such structures an inherently 20 process since the tunneling probability depends not only on the electron's momentum perpendicular to the tunnehng barrier but also on its momentum parallel to the barrier. Pronounced resonances are obtaitted for the tunneling probability and the conductance of a resonant tunneling device consisting of such magnetic barriers.

Magnetic Quantum Dot: A Magnetic Transmission Barrier and Resonator

“…The study of such a scattering mechanism is important to understanding the electron transport in magnetic structures and to suggesting future device applications. However, to our knowledge, little attention has been paid to it [7].In this Letter, we study the ballistic transport of conventional edge channels through quantum wires with a magnetic quantum dot. The magnetic edge states near the dot and the two-terminal conductance G(E F ) of the wires in the zero bias limit are found to exhibit distinct features between two cases of γ > 0 and γ < 0, where E F is the Fermi energy.…”

“…Various magnetic structures such as magnetic dots [1], superlattices [2], barriers [3], and transverse steps [4] were realized experimentally in nonplanar 2DEGs or by patterning ferromagnetic or superconducting materials. Theoretically, it was shown that nonuniform magnetic fields can cause electron drifts [5,6], transmission barriers [7], and commensurability effects [8]. Magnetic edge states, which exist along the boundary between two different magnetic domains, were proposed [9,10] in the analogy with the conventional edge states [11] in quantum Hall systems, and their effects on magnetoresistance were reported experimentally [4].…”

Magnetic Confinement of Massless Dirac Fermions in Graphene

“…transport in the presence of magnetic barriers [11] and superlattices [12], magnetic edge states close to a magnetic step [13], and magnetically confined quantum dots or antidots [14]. Correspondingly, apart from one study of magnetic edge states in narrow-gap semiconductors [15], model calculations have only been carried out for Schrödinger fermions [10,16,17,18], Here we formulate the theory of magnetic barriers and magnetic quantum dots for the massless Dirac-Weyl fermions in graphene. With minor modifications, the theory also covers narrow-gap semiconductors.…”

Quantum spin pumping with adiabatically modulated magnetic barriers

“…10-12) in the weak pumping regime one can easily notice that this sinusoidal dependence arises because of the sin(2k 2 d) factor in the numerator of Eqs. [10,11]. One can approximate g ′ ∼ 1 as g * = 0.44 for GaAs based system and thus the pumped current becomes-…”

“…Magnetic barrier's can not only be formed by this method but also when a conduction stripe with current driven through it is deposited on a 2DEG, and also when a super-conductor plate is deposited on a 2DEG, see Refs. [9,10] for details.…”