Enhancement of Spin Lifetime in Gate-Fitted InGaAs Narrow Wires

Abstract

We investigated the spin lifetime in gate-fitted InGaAs narrow wires from magnetotransport measurement. Applying positive gate bias voltage, the spin lifetimes in narrow wires became more than one order longer than those obtained from a Hall bar sample with two-dimensional electron gas. This enhancement of spin lifetime in gated wires is the first experimental evidence of dimensional confinement and resonant spin-orbit interaction effect controlled by gate bias voltage. Spin relaxation due to the cubic Dresselhaus term is negligible in the present InGaAs wires.

Spin and phase coherence lengths inn-InSbquasi-one-dimensional wires

“…4, it follows that L S ϰ 2.4͑L ⍀ 2 / w͒. The proportionality factor 2.4 holds, within experimental error, up to T Ϸ 5 K. As has been observed previously, 8 L S is enhanced even in wires where w Ͼ L ⍀ . We are not aware of theoretical predictions for enhanced L S in ballistic wires which consider both Rashba and cubic Dresselhaus SOI.…”

“…For w = 0.16 m, ͉⌬G͑B cr ͉͒ is a factor ϳ6 smaller than for w = 0.56 m. A suppression of antilocalization in narrow wires has been previously observed in other systems. [7][8][9]35 In addition, the narrowest wires show the strongest T dependence of the negative magnetoconductance around B = 0. Negative magnetoconductance is not observed above 5 K in the narrowest wires but is still evident at 15 K in the wider wires, according to Fig.…”

“…Thus quantitative information about both L S and L can be obtained from magnetotransport measurements. 5,[10][11][12][13][14][15][16][17][18][19][20][21][22][23] Extensive experimental and theoretical research on antilocalization phenomena in thin films of metals [11][12][13] and semiconductors, [23][24][25] in 2DESs, [14][15][16][17][18][19][20][26][27][28][29][30][31][32] in hole systems, 22,33 and in narrow wires [7][8][9][34][35][36] demonstrate that these measurements form a valuable experimental tool for investigating spin and phase coherence in various material systems.…”

Spin-orbit interaction and phase coherence in lithographically defined bismuth wires

“…Further, τ so increases as W decreases. In semiconductor 2DESs, where the SOI is dominated by inversion asymmetry via the structural Rashba and Dresselhaus terms, experiments and theory have verified 20,[24][25][26][27][28][29] that τ so ∝ W −1/2 . A similar dependence has not been proposed in the 3-dimensional bulk for SOI in heavy metallic elements like Bi.…”

“…For structural SOI, theory predicts that in quasi-one-dimensional (Q1D) wires, τ so increases with decreasing wire width 24,25 , indeed experimentally supported for various 2DESs 20,[26][27][28][29] . As yet, no similar theoretical predictions exist for SOI due to heavy elements, present in bulk Bi.…”