DFG-RSF: Nonequilibrium Phenomena and Interactions in Ultrapure III-V Nanowires

半导体纳米线（SNW）由于其材料组合的灵活性和其固有的一维几何形状而被广泛探索，这允许以前所未有的方式定制其物理性质，并在纳米电子学、自旋电子学、纳米光子学和热电学中打开独特的机会。然而，许多应用的电子性能要求仍然超过通常可用的SNW。因此，本提案的一个主要目标是实现具有非常高的电荷载流子迁移率和/或大的自旋-轨道相互作用的超纯III-V基SNWs。我们的高质量SNWs将特别适合于我们提案的第二个主要目标，即研究SNWs中电荷载流子的复杂相互作用动力学，这是大多数应用的核心。基于我们的高品质InAs，InSb和调制掺杂的GaAs-AlGaAs核壳SNW，我们的目标是完全控制其固有的结构和电子特性，使扩散和弹道输运制度之间的可调谐性。我们的实验的重点在于研究多体相关性，这是在一维系统中增强（应该是清楚可见的弹道SNW），自旋轨道相互作用的散射动力学的影响，以及非弹性散射和电子-声子相互作用。除了通过场效应门接触和控制SNW的标准光刻技术之外，我们还将实现基于轴向异质结构或超晶格的固有生长势垒，例如为声子创建布拉格反射镜以促进电子-声子相互作用。此外，我们将优化欧姆接触和创造超导接触的原位再生长。低电阻欧姆接触对于研究弹道输运机制是必不可少的，超导接触将使我们能够实现不寻常的非平衡准粒子分布。为了实现所有这些目标，我们联合收割机结合了一个多学科团队的核心专业知识，该团队已经活跃在超纯SNW的合成和表征，先进的量子输运光谱学和非平衡纳米电子学，以及主要噪声和扫描门测量。该项目将在分子束外延生长超纯和定制SNW，理解相关效应和非平衡相互作用方面取得重要进展。

Semiconductor nanowires (SNW) are widely explored because of their flexibility in material combinations and their inherent one-dimensional geometry, which allow to tailor their physical properties in an unprecedented way and open unique opportunities in nanoelectronics, spintronics, nanophotonics and thermoelectrics. However, many applications have electronic property requirements still exceeding that of commonly available SNWs. Therefore, one main objective of this proposal is to realize ultra-pure III-V-based SNWs with intrinsically very high charge carrier mobility and/or large spin-orbit interaction.Our high quality SNWs will be particularly tailored for the second main objective of our proposal, namely to study the complex interaction dynamics of the charge carriers in SNWs being at the heart of most applications. Based on our high quality InAs-, InSb- and modulation-doped GaAs-AlGaAs core-shell SNWs, we aim at the full control of their intrinsic structural and electronic properties to enable tunability between the diffusive and ballistic transport regimes. The focus of our experiments then lies on studying many-body correlations which are enhanced in one-dimensional systems (and should be clearly visible in ballistic SNWs), the influence of spin-orbit interaction on the scattering dynamics, as well as inelastic scattering and electron-phonon interaction. Next to standard lithography techniques to contact and control the SNWs via field effect gates we will also implement intrinsically grown barriers based on axial heterostructures or superlattices, for instance to create Bragg mirrors for phonons to foster the electron-phonon interaction. Further, we will optimize ohmic contacts and create superconducting contacts by in-situ regrowth. Low resistive ohmic contacts are essential for studying the ballistic transport regime and superconducting contacts will allow us to realize unusual nonequilibrium quasiparticle distributions.To reach all these goals in this proposal we combine the core expertise of a multidisciplinary team already active in the synthesis and characterization of ultra-pure SNWs, advanced quantum transport spectroscopy and nonequilibrium nanoelectronics, as well as primary noise and scanning gate measurements. This project will provide an important progress in the MBE growth of ultra-pure and tailored SNWs, understanding of correlation effects and nonequilibrium interactions therein.