CAREER: Nanoscale Ballistic Spin Transport in Semiconductors

University Of Kansas Center For Research Inc, Lawrence KS

Investigators

Abstract

****NON-TECHNICAL ABSTRACT**** Along with charge, electrons have a quantum mechanical property known as ?spin.? A future technology that would be based on the spin of electrons has been named ?spintronics.? Spintronic devices are expected to be more powerful, less expensive, lighter, and consume less energy than the present electronic devices. To develop this spin-based technology, it is necessary to study movement of spin in semiconductors. This Faculty Early Career Award supports a project that will investigate nanometer-scale spin transport in semiconductors. So far, most studies have focused on spin transport at the micrometer or even larger length scales. To integrate spintronics with nanotechnology, it is crucial to understand and control nanometer-scale spin transport in semiconductors. Such transport will take place on very short timescales. This project will address this key issue using novel laser techniques that are capable of detecting events as fast as 70 femtoseconds and spin movements as small as one hundredth of nanometer. Gallium Arsenide and its nanostructures will be used to study several key aspects of the collision-free spin transport (known as ballistic spin transport). This project will advance our knowledge of spin dynamics in semiconductors, and provide comprehensive information for nanoscale spintronics. The education component of this project is well integrated with the research efforts. A new course on laser principles and techniques will be developed. The cutting edge research will involve graduate and undergraduate students, as well as high-school teachers. Outreach projects concerning what happens at very short time scales as well as projects concerning fundamental processes in materials will also be developed based on the research topics. ****TECHNICAL ABSTRACT**** This Faculty Early Career Award supports experimental investigations of nanoscale ballistic spin transport in semiconductor bulk, quantum wells and quantum wires. Spin transport is a fundamental process in spintronic devices. So far, most studies have focused on transport on large length scales where the transport is dominated by the drift-diffusion processes. Since the size of electronic devices on integrated circuits has been reduced to 60 nm, which is comparable to or even smaller than the mean free path of electrons, it is necessary to understand and control ballistic spin transport on the nanoscale. In this project, nanoscale spin transport in semiconductors will be studied by using ultrafast laser techniques with a temporal resolution of 70 femtoseconds and a capability of detecting movements as small as 10 picometers. Nanoscale ballistic spin transport will be directly observed and studied by tracking the position of spins in real space and real time. Several key aspects of ballistic spin transport will be studied. The proposed research will provide comprehensive information for nano-spintronics and reveal rich physics involved in ballistic spin transport. The education component of this project is well integrated with the research efforts. A new course on laser principles and techniques will be developed. The cutting edge research will involve graduate and undergraduate students, as well as high-school teachers. Outreach projects will also be developed based on the research topics.