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项目支持辛辛那提大学开发一种独特的仪器，该仪器将促进对整个半导体材料类别的理解，为这些纳米结构的新应用提供基础。小尺寸（纳米级）和大的自旋轨道相互作用的结合可能使这些材料能够以非常高的速度和低能量运行，这些设备可能取代目前的硅基电路。参与该仪器开发的研究生将学习技术技能，并将发展实质性的设计技能。一家电子公司的参与，生产成像产品在这种能源制度，提供了互动的基础，可以为公司指出新的方向，并导致未来的合作研究努力。该提案的研究成果将被纳入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纳米日。飞秒泵浦探测光散射仪的研制，将使具有极强自旋轨道相互作用和中红外间隙的单纳米结构的电子动力学和自旋动力学研究成为可能。由于缺乏广泛可调谐的激光源或灵敏的探测器，中红外0.1至1 eV能量范围面临着重大挑战。这种中红外能量范围涵盖了整个半导体材料，由于它们具有极大的自旋-轨道耦合，可以使用联合电场和磁场探索和操纵自旋，因此激发了理论和实验的兴趣。该发展方案利用了两种新开发的技术来测量单个纳米结构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，并用延迟探针脉冲询问电子结构的非平衡居群。

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.