中红外光学自旋注入与相干控制
Mid-Infrared Optical Spin Injection and Coherent Control
AI总结：
该研究针对硅兼容Ge₁₋ₓSnₓ半导体，通过全布里渊区30带k·p方法分析中红外波段光学自旋注入与相干控制，揭示Sn组分对自旋极化度等的调控规律，为分子指纹区量子相干操控提供材料基础。
摘要：
本文研究了Ge₁₋ₓSnₓ半导体中电荷与自旋电流的光学注入效应随Sn组分的变化规律。这类新兴的硅兼容材料可在整个中红外波段实现对上述过程的调制。在独立粒子近似下，阐明了单光子与双光子带间吸收过程，并讨论了三种不同偏振构型下相干控制的演化规律。为评估高能跃迁的贡献，计算中采用了全布里渊区30带k·p方法。研究发现，除了预期的直接带隙窄化及相应的吸收长波偏移外，在Ge中掺入Sn还会提升E₁共振处的单光子自旋极化度（DSP）。此外，随着Sn组分增加，带边附近响应张量的幅值呈指数增强，这一行为可归因于Sn掺入导致的载流子有效质量降低。至少在低Sn组分下，纯自旋电流注入在E₁共振处也呈现出相同趋势。带边处的双光子自旋极化度超过纯Ge中的数值，在Sn组分高于14%时达到60%。这些结果表明，Ge₁₋ₓSnₓ半导体可用于实现与量子传感相关的分子指纹区的量子相干操控。
英文摘要：
The optical injection of charge and spin currents are investigated in Ge$_{1-x}$Sn$_{x}$ semiconductors as a function of Sn content. These emerging silicon-compatible materials enable the modulation of these processes across the entire mid-infrared range. Under the independent particle approximation, the one- and two-photon interband absorption processes are elucidated, and the evolution of the coherent control is discussed for three different polarization configurations. To evaluate the contribution of high-energy transitions, a full-zone 30-band k$\cdot$p is employed in the calculations. It was found that, besides the anticipated narrowing of the direct gap and the associated shift of the absorption to longer wavelengths, incorporating Sn in Ge also increases the one-photon degree of spin polarization (DSP) at the $E_1$ resonance. Moreover, as the Sn content increases, the magnitude of the response tensors near the band edge exhibits an exponential enhancement. This behavior can be attributed to the Sn incorporation-induced decrease in the carrier effective masses. This trend appears to hold also at the $E_1$ resonance for pure spin current injection, at least at low Sn compositions. The two-photon DSP at the band edge exceeds the value in Ge to reach 60 % at a Sn content above 14 %. These results demonstrate that Ge$_{1-x}$Sn$_{x}$ semiconductors can be exploited to achieve the quantum coherent manipulation in the molecular fingerprint region relevant to quantum sensing.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
