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

半导体纳米线(SNW)因其在材料组合上的灵活性和固有的一维几何结构而被广泛探索，这使得它们能够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领域开辟了独特的机会。然而，许多应用对电子特性的要求仍然超过了通常提供的SNW。因此，该方案的一个主要目标是实现具有本质上非常高的载流子迁移率和/或大的自旋-轨道相互作用的超纯III-V基单壁波。我们的高质量单壁波将特别为我们建议的第二个主要目标量身定做，即研究处于大多数应用核心的单壁波中电荷载流子的复杂相互作用动力学。基于我们的高质量InAs、InSb和调制掺杂的GaAs-AlGaAs核壳结构单壁波导，我们的目标是完全控制它们的固有结构和电子性质，以便能够在扩散和弹道输运模式之间进行调谐。我们的实验重点是研究在一维系统中增强的多体关联(在弹道单波中应该是清晰可见的)，自旋-轨道相互作用对散射动力学的影响，以及非弹性散射和电子-声子相互作用。除了标准的光刻技术通过场效应门接触和控制声子波外，我们还将实现基于轴向异质结构或超晶格的本征生长势垒，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，并通过原位再生长来创建超导接触。低阻欧姆接触是研究弹道传输机制的关键，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，在这个提议中，我们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和非平衡纳米电子学以及初级噪声和扫描门测量方面。该项目将在超纯和定制单壁晶体的分子束外延生长、了解其中的关联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.