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Tunable interfacial Rashba spin-orbit coupling in asymmetric Al$_x$In$_{1-x}$Sb/InSb/CdTe quantum well heterostructures
Hanzhi Ruan, Zhenghang Zhi, Yuyang Wu, Jiuming Liu, Puyang Huang, Shan Yao, Xinqi Liu, Chenjia Tang, Qi Yao, Lu Sun, Yifan Zhang, Yujie Xiao, Renchao Che, Xufeng Kou
TL;DR
The paper examines how heterostructure design shapes Rashba spin-orbit coupling in AlxIn1-xSb/InSb/CdTe quantum wells. It reports MBE-grown structures, aligned built-in fields at both interfaces, and a possible role for interfacial electron confinement in enhancing the Rashba coefficient.
Problem
The paper addresses the design of heterostructures for Rashba-type spintronic devices and whether interfacial electron confinement may enhance the Rashba coefficient.
Source: pp. 3, 9Method
The study reports AlxIn1-xSb/InSb heterostructures grown by molecular beam epitaxy and analyzes samples using a D’yakonov-Perel-based ILP model.
Source: pp. 3, 4, 6Results
DPC confirms that built-in electric fields at both hetero-interfaces point in the same direction, while carrier mobility and density are tabulated across Al-content samples at 1.5 K.
Source: Figure Caption · pp. 14–15Takeaways & Limitations
The passages frame dedicated heterostructure design as relevant to energy-efficient Rashba devices, with greater interfacial electron confinement proposed as a possible way to enhance αR.
Source: pp. 3, 9Lattice-constant mismatch with InSb may introduce interfacial defects and alloy scattering that degrade channel mobility at low temperatures.
Source: p. 5
Abstract
from arXiv · showhide
The manipulation of Rashba-type spin-orbit coupling (SOC) in molecular beam epitaxy-grown Al$_x$In$_{1-x}$Sb/InSb/CdTe quantum well heterostructures is reported. The effective band bending provides robust two-dimensional quantum confinement, while the unidirectional built-in electric field from the asymmetric hetero-interfaces results in pronounced Rashba SOC strength. By tuning the Al concentration in the top Al$_x$In$_{1-x}$Sb barrier layer, the optimal structure with $x = 0.15$ shows the largest Rashba coefficient of 0.23 eV-Angstrom. and the highest low-temperature electron mobility of 4400 cm$^2$/Vs . Quantitative investigations of the weak anti-localization effect further confirm the dominant D'yakonov-Perel (DP) spin relaxation mechanism during charge-to-spin conversion. These findings highlight the significance of quantum well engineering in shaping magneto-resistance responses, and narrow bandgap semiconductor-based heterostructures may offer a reliable platform for energy-efficient spintronic applications.
Data Availability
The study’s supporting data are available from the corresponding author upon reasonable request. The statement defines these data as the minimum needed to interpret, replicate, and build on the reported findings.
Data Availability
- The statement encourages deposition in public repositories when available and appropriate, or presentation in the manuscript.It describes these as encouraged routes for sharing data.Source: Data Availability · p. 10
- The statement defines supporting data as the minimum dataset needed to interpret, replicate, and build on the reported findings.This specifies the intended scope of the dataset.Source: Data Availability · p. 10
- The study’s supporting data are available from the corresponding author upon reasonable request.The availability statement identifies the corresponding author as the source.Source: Data Availability · p. 10
Figure Caption:
The figure-caption material covers the heterostructure’s band diagram and interfaces, the direction of its built-in fields, and comparisons of transport and Rashba-related measures across samples and material systems.
Figure Caption:
- The band diagram depicts the asymmetric AlxIn1-xSb/InSb/CdTe quantum well structure, and the caption identifies TCAD simulation.The supplied caption text identifies the diagram as the right-hand panel.Source: Figure Caption · p. 14
- The growth caption identifies a 30 nm InSb channel and a 40 nm AlxIn1-xSb barrier with 0 < x ≤ 0.18.It also refers to in-situ RHEED patterns after deposition of these layers.Source: Figure Caption · p. 14
- The microscopy images distinguish both hetero-interfaces and describe the crystalline configuration as well ordered, without notable defects.The caption refers to the AlInSb/InSb and InSb/CdTe interfaces.Source: Figure Caption · p. 14
- DPC mapping confirms that built-in electric fields at both hetero-interfaces point in the same direction.The figure caption identifies the sample as Al0.15In0.85Sb/InSb/CdTe and notes that the color wheel designates field direction.Source: Figure Caption · p. 14
- The captions compare Rashba coefficients and phase-coherent lengths among Samples A–D, and compare Rashba coefficients across strong-SOC material systems.Another caption fragment identifies data at 1.5 K and 20 K.Source: Figure Caption · p. 15
- At 1.5 K, the table reports carrier mobility and density for samples with Al contents x = 0.1, 0.13, 0.15, and 0.18.The table headings identify mobility and carrier density as the reported measures.Source: Figure Caption · pp. 15, 19