The spin-orbit (SO) coupling parameters for lowest conduction subband due to structural (SIA) and bulk (BIA) inversion asymmetry are calculated for a range of carrier densities in [001]-grown delta-doped n-type InSb/In1-xAlxSb asymmetric quantum wells using the established 8 band k.p formalism [PRB 59,8 R5312 (1999)]. We present calculations for conditions of zero bias at 10 K. It is shown that both the SIA and BIA parameters scale approximately linearly with carrier density, and exhibit a marked dependence on well width when alloy composition is adjusted to allow maximum upper barrier height for a given well width. In contrast to other material systems the BIA contribution to spin splitting is found to be of significant and comparable value to the SIA mechanism in these structures. We calculate the spin lifetime for spins oriented along [11-0] based on D'yakonov-Perel mechanism using both the theory of Averkiev et al. [J. Phys.:Condens. Matter 14 (2002)] and also the rate of precession of spins about the effective magnetic field, taking into account all three SO couplings, showing good agreement.Spin lifeime for this direction is largest in the narrow wells over the range of moderate carrier densities considered, which is attributed to the reduced magnitude of the k-cubic BIA parameter in narrow wells. The inherently large BIA induced SO coupling in these systems is shown to have considerable effect on the spin lifetime, which exhibits significant reduction in the maximum spin lifetime compared to previous studies which consider systems with relatively weak BIA induced SO coupling. The relaxation rate of spins oriented in the [001] direction is dominated by the k-linear SIA and BIA coupling parameters and at least an order of magnitude greater than in the [11-0] direction.
Fabrication and characterization of InSb nanosheet/hBN/graphite heterostructure devices
制备了半导体InSb纳米片/六方氮化硼（hBN）/石墨三层结构，并实现了由三层结构制成的单栅和双栅器件，并进行了表征。在三层装置中采用的InSb纳米片是外延生长的、独立的锌晶体，并且横向尺寸为微米。通过剥离获得hBN和石墨薄片。每个三层通过使用自制的对准堆叠/转移装置在hBN薄片和石墨薄片上连续堆叠InSb纳米片来制成。所制造的单和双栅极器件的特征在于通过电和/或磁输运测量。在所有这些器件中，石墨和hBN薄片被用作底栅和栅衬。对所制备的单底栅场效应器件的测量表明，器件中InSb纳米片的电子场效应迁移率为~7300 cm $^2$ V $^{-1}$ s $^{-1}$，在1.9 K时栅滞后为~0.05 V。双栅霍尔栅器件的测量结果表明，顶部和底部的栅极表现出很强的电容耦合到InSb纳米片沟道，从而可以有效地调整纳米片沟道传导。在霍尔条器件的InSb纳米片中的电子霍尔迁移率被提取为大于1.1 $\times$ 10 $^4$ cm $^2$ V $^{-1}$ s $^{-1}$，在~6.1 $\times$ 10 $^{11}$ cm $^{-2}$和1.9 K的片电子密度下，并且因此，该器件表现出明确的舒布尼科夫-德哈斯振荡。
Spin transport analysis for a spin pseudovalve-type L_l/SC/L_r trilayer for L = {FeCr, Fe, Co, NiFe, Ni} and SC = {GaSb, InSb, InAs, GaAs, ZnSe}
Instituto de Física La Plata IFLP-CONICET, CCT La Plata. Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata UNLP（拉普拉塔物理研究所 (IFLP-CONICET)、拉普拉塔中央科学技术区、拉普拉塔国立大学理学院）；Grupo de Ciencia y Tecnología de Materiales Cerámicos CYTEMAC, Departamento de Física, Facultad de Ciencias Naturales, Exactas y de la Educación, Universidad del Cauca UNICAUCA（考卡大学自然科学、精确与教育学院物理系陶瓷材料科学与技术小组）
Spin-orbit interactions in inversion-asymmetric 2D hole systems: a variational analysis
本文深入研究了半导体异质界面上反转非对称二维空穴气体中的自旋轨道相互作用。我们专注于常见的半导体，如GaAs，InAs，InSb，Ge和Si。我们开发了一个半解析变分方法来量化SO相互作用，占结构反转不对称性（SIA）和散装反转不对称性（BIA）。在某些情况下，使用Schriffon-Wolff（SW）变换，基态重空穴子带的色散可以写为$E(k) = A k^2 - B k^4 \pm C k^3$，其中$A$、$B$和$C$是材料和结构相关的系数。我们提供了一个简单的方法来计算参数$A$，$B$，和$C$，但表明，简单的SW近似导致的SIA（Rashba）自旋分裂$\propto k^3$频繁故障。我们确定的参数制度，在这种情况下发生上述材料，并讨论了一个方便的半分析方法，以获得正确的自旋分裂，有效质量，费米能级，和子带占用率，连同它们的依赖性的电荷密度，掺杂剂类型，和掺杂剂浓度的反型和积累层。我们的结果与完全数值计算以及与实验结果吻合得很好。他们认为简单立方Rashba模型的简单应用在常见的异质结构以及量子点中的应用有限。最后，我们发现，对于这里研究的单异质结的BIA项的幅度总是比SIA项的幅度小得多。
