Effect of the tilted magnetic field on the magnetosubbands and conductance in the bilayer quantum wire

Abstract

The single electron magnetotransport in a vertical bi-layer semiconductor nanowire made of InAlAs/InGaAs and AlGaAs/GaAs heterostructure is theoretically studied. The magnetic field is directed perpendicularily to the main (transport) axis of the quantum wire and both non-zero components of magnetic field, that is the transverse and the vertical ones, allow to change the magnitude of intra-layer and inter-layer subbands mixing, respectively. We analyze in detail the changes introduced to energy dispersion relation E(k) by strong titled magnetic field up to several teslas for a symmetric and an asymmetric confining potential in the growth direction. These calculated energy dispersion relations are thereafter used to show that the value of conductance of bi-layer nanowire may jump as well as drop by few conductance quanta when the Fermi energy is changed what in conjunction with spin Zeeman effect may give a moderately spin polarized current.

Effect of picosecond magnetic pulse on dynamics of electron's subbands in semiconductor bilayer nanowire

“…However, an intersubband scattering without change of wave vector k can still occur since it corresponds to mixing of two subbands by e.g. variations of B y what locally influences on energy subbands' dispersions 12,13 and according to formula (5) on group velocities.…”

“…[10][11][12][13] Such hybridization is activated by the off-diagonal elements in Hamiltonian what transforms the subbands crossings in energy spectrum into avoiding crossings called pseudogaps. 10,12 Occurrence of pseudogaps is visible as sudden drop in conductance for increasing Fermi energy what can be realized by applying appropriate voltages to the top and back gates. 3,15 In recent years, attention of researchers mainly attract the many-body effects appearing in bilayer nanosystems which can be examined in quantum transport measurements.…”

“…the width of a barrier separating the wires, can be selectively modified by applying external magnetic field. 1,2,[9][10][11][12][13] In particular the in-plane orientation of magnetic field plays a crucial role in transport measurements. Fischer et all.…”

“…14 Second, it hybridizes the ground state and first excited state in vertical direction what modifies the energy subbands. [10][11][12][13] Such hybridization is activated by the off-diagonal elements in Hamiltonian what transforms the subbands crossings in energy spectrum into avoiding crossings called pseudogaps. 10,12 Occurrence of pseudogaps is visible as sudden drop in conductance for increasing Fermi energy what can be realized by applying appropriate voltages to the top and back gates.…”

Application of the Picosecond Magnetic Pulses for Inducing the Electron Motion in the Bilayer Nanowire

“…Briefly, the static magnetic field may diminish the interlayer coupling if it is directed along the wire (longitudinal magnetic field) [1,2], hybridize the electrons subbands in each layer separately if it is perpendicular to the wire axis and the layers [3][4][5], or, mix the subbands originated in different layers if it is simultaneously parallel to the layers and perpendicular to the transport axis [5]. Here, we consider the reverse of the last case, that is, we study the effect of the timevarying magnetic field on the dynamics of the electron which is initially at rest.…”