Strongly modulated transmission of a spin-split quantum wire with local Rashba interaction - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




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Abstract: We investigate the transport properties of ballistic quantum wires in thepresence of Zeeman spin splittings and a spatially inhomogeneous Rashbainteraction. The Zeeman interaction is extended along the wire and producesgaps in the energy spectrum which allow electron propagation only for spinorslying along a certain direction. For spins in the opposite direction the wavesare evanescent far away from the Rashba region, which plays the role of thescattering center. The most interesting case occurs when the magnetic field isperpendicular to the Rashba field. Then, the spins of the asymptoticwavefunctions are not eigenfunctions of the Rashba Hamiltonian and theresulting coupling between spins in the Rashba region gives rise to suddenchanges of the transmission probability when the Fermi energy is swept alongthe gap. After briefly examining the energy spectrum and eigenfunctions of awire with extended Rashba coupling, we analyze the transmission through aregion of localized Rashba interaction, in which a double interface separates aregion of constant Rashba interaction from wire leads free from spin-orbitcoupling. For energies slightly above the propagation threshold, we find theubiquitous occurrence of transmission zeros antiresonances which are analyzedby matching methods in the one-dimensional limit. We find that a a minimaltight-binding model yields analytical transmission lineshapes of Fanoantiresonance type. More general angular dependences of the external magneticfield is treated within projected Schroedinger equations with Hamiltonianmatrix elements mixing wavefunction components. Finally, we consider arealistic quantum wire where the energy subbands are coupled via the Rashbaintersubband coupling term and discuss its effect on the transmission zeros.



Author: David Sanchez, Llorens Serra, Mahn-Soo Choi

Source: https://arxiv.org/







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