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)和大自旋-轨道相互作用的结合可能使这些材料以非常高的速度和低能量运行，这些设备可能会取代当今基于硅的电路。参与该仪器开发的研究生将学习技术技能，并将发展大量的设计技能。一家在这种能源制度下制造成像产品的电子公司的参与，为互动提供了基础，这些互动可能为公司指明新的方向，并导致未来的合作研究努力。这项建议的研究工作将纳入持续的公众宣传工作所使用的材料，包括辛辛那提博物馆中心的NanoDays。飞秒泵浦-探测光散射仪的开发将使对单个纳米结构的电子和自旋动力学的新研究成为可能，这些结构在中红外具有极强的自旋轨道相互作用和间隙。由于缺乏可广泛调谐的激光光源或灵敏探测器，中红外0.1至1 eV的能量范围构成了巨大的挑战。这个中红外能量范围涵盖了一整类半导体材料，这些材料由于其极大的自旋-轨道耦合而引起了理论和实验的兴趣，这使得利用电场和磁场来探索和操纵自旋成为可能。这一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，这些技术将被扩展到这个中红外能量范围：(A)瞬时瑞利散射谱(TRRS)，其中泵浦脉冲激发纳米结构，并且从延迟的探测脉冲散射的光来询问复折射率；以及(B)瞬时光电流谱(TPCS)，其中泵浦脉冲激发单个纳米结构器件中的光电流，并且用延迟的探测脉冲来询问电子结构的非平衡布居。

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.