Spin–orbit induced electronic spin separation in semiconductor nanostructures

Abstract

The demonstration of quantized spin splitting by Stern and Gerlach is one of the most important experiments in modern physics. Their discovery was the precursor of recent developments in spin-based technologies. Although electrical spin separation of charged particles is fundamental in spintronics, in non-uniform magnetic fields it has been difficult to separate the spin states of charged particles due to the Lorentz force, as well as to the insufficient and uncontrollable field gradients. Here we demonstrate electronic spin separation in a semiconductor nanostructure. To avoid the Lorentz force, which is inevitably induced when an external magnetic field is applied, we utilized the effective non-uniform magnetic field which originates from the Rashba spin–orbit interaction in an InGaAs-based heterostructure. Using a Stern–Gerlach-inspired mechanism, together with a quantum point contact, we obtained field gradients of 108 T m−1 resulting in a highly polarized spin current.

Demonstration of gate control of spin splitting in a high-mobility InAs/AlSb two-dimensional electron gas

“…Control over spin-orbit interaction in semiconductors is necessary for developing novel spin-based electronics [2][3][4] and studying phenomena mediated by spin-orbit coupling 5 , which include spin filtering techniques 6,7 , spin-orbit qubits 8,9 , all-semiconductor spin-FETs 10,11 , and topological superconductivity in semiconductor-superconductor heterostructures [12][13][14][15] . In addition to strong spin-orbit coupling, low-dimensional systems require sufficiently high carrier mobility to enable their utilization for quantum information processing 16 .…”

“…Longitudinal resistance was measured in the [1][2][3][4][5][6][7][8][9][10] crystallographic direction.…”

Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts

“…In spite of various experimental attempts on the shot noise in QPC, many research groups have been repeatedly reporting an interesting observation, that is, an enhanced QPC shot noise exceeding theoretical value 24,[26][27][28][29][30][31] . This deviation was attributed to several reasons: the 1/f noise, the channel mixing, and the electron heating as the most likely one 31 .…”

“…Since this theory is based on the single-particle picture, additional information such as the many-body interaction may be deduced from the precise investigation of the Fano factor combined with the conductance, as we see in the shot noise study in the Kondo regime [19][20][21][22] . Actually, the shot noise of QPC was addressed by several experimental groups; the Pauli exclusion principle was first studied, and then the quantum interference 23 , the 0.7 anomaly [24][25][26] , and the spin polarization 25,27 .…”

Spin Blocker Using the Interband Rashba Effect in Symmetric Double Quantum Wells

“…The generation of spins in nonmagnetic semiconductors is attracting increasing interest not only for applications like the Datta-Das spin-FET [1,2] but also from a basic science viewpoint, such as the confirmation of the RashbaEdelstein effect [3][4][5][6][7], the intrinsic and extrinsic spin-Hall effect [8][9][10][11], spin-filtering devices using resonant tunneling diodes [12][13][14], and spin-dependent phenomena in quantum-point-contact devices [15][16][17][18].…”