MRI: Development of a Mid-infrared Optical Microscope for Investigation of Femtosecond Dynamics of Single Large Spin Orbit Semiconductor Heterostrucutures

材料研究部和主要研究仪器计划支持辛辛那提大学开发一种独特的仪器，该仪器将促进对整类半导体材料的理解，为这些纳米结构的新应用提供基础。小尺寸（纳米级）和大自旋轨道相互作用的结合可以使这些材料能够以可能取代当今硅基电路的设备所需的非常高的速度和低能量运行。 参与该仪器开发的研究生将学习技术技能并培养大量的设计技能。 一家在这种能源体制下生产成像产品的电子公司的参与，为互动奠定了基础，为公司指明了新的方向，并促成了未来的合作研究工作。该提案的研究工作将包含在用于持续公共宣传工作的材料中，包括辛辛那提博物馆中心的 NanoDays。飞秒泵浦探针光散射仪器的开发将使对单一纳米结构的电子和自旋动力学的新研究成为可能，这些纳米结构在中红外区域具有极强的自旋轨道相互作用和间隙。 由于缺乏广泛可调的激光源或灵敏的探测器，中红外 0.1 至 1 eV 能量范围提出了重大挑战。这个中红外能量范围涵盖了一整类半导体材料，这些材料因其极大的自旋轨道耦合而引起了理论和实验的兴趣，这使得能够利用电场和磁场的组合来探索和操纵自旋。 该开发提案利用了两项新开发的技术来测量单个纳米结构中的能量结构和飞秒动力学，这些技术将扩展到中红外能量范围：（A）瞬态瑞利散射光谱（TRRS），其中泵浦脉冲激发纳米结构，并且通过延迟探测脉冲​​散射的光来询问复折射率； (B) 瞬态光电流光谱 (TPCS)，其中泵浦脉冲在单个纳米结构器件中激发光电流，并用延迟的探测脉冲询问电子结构的非平衡群体。

The Division of Materials Research and the Major Research Instrumentation program supports the University of Cincinnati with the development of a unique instrument that will advance the understanding of a whole class of semiconductor materials that can provide the basis for new applications of these nanostructures. The combination of small size (in the nanoscale) and large spin-orbit interactions may enable these materials to operate at the very high speeds and low energies required for devices which might replace present day silicon-based circuits. Graduate students involved in the development of this instrument will learn technical skills and will develop substantial design skills. Involvement of an electronics company, which makes imaging products in this energy regime, provides the basis for interactions that could point to new directions for the company and result in future collaborative research efforts. Research efforts of this proposal will be included in the materials used for continuing public outreach efforts, including NanoDays at the Cincinnati Museum Cente.The development of a femtosecond pump-probe light scattering instrument will enable new studies of electronic- and spin-dynamics of single nanostructures which have extremely strong spin-orbit interactions and gaps in the Mid-Infrared. The mid-infrared 0.1 to 1 eV energy range poses significant challenges because of the lack of widely tunable laser sources or sensitive detectors. This mid-IR energy range covers an entire class of semiconductor materials which have excited both theoretical and experimental interest because of their extremely large spin-orbit coupling which enables the exploration and manipulation of spins using combined electric and magnetic fields. This development proposal takes advantage of two newly developed techniques for measuring energy structure and femtosecond dynamics in single nanostructures which will be extended into this mid-IR energy range: (A) Transient Rayleigh Scattering Spectroscopy (TRRS), where a pump pulse excites the nanostructure and the complex index of refraction is interrogated by the light scattered from a delayed probe pulse; and (B) Transient Photocurrent Spectroscopy (TPCS), where a pump pulse excites a photocurrent in a single nanostructure device and the non-equilibrium population of the electronic structure is interrogated with a delayed probe pulse.