CAREER: Spin-Spin Interactions, Magnetic Order and Low-Dimensional Effects in Magnetic Semiconductors: Education and Research at the Nanoscale with Spin-Polarized STM

Boston College, Chestnut Hill MA

Investigators

Abstract

Non-technical abstract In the last few years, the possibility of a new generation of spin based devices (spintronics), has given impetus to fundamental studies of magnetic systems. Spin based devices have the potential to be faster and consume less power than traditional charge based electronics. Dilute magnetic semiconductors (DMS) are currently being pursued as one of the most promising avenues of realizing spintronic devices, but the lack of semiconductors with magnetic carriers at room temperature remains a significant bottleneck in this endeavor. The goal of this Faculty Early Career project is to explore the fundamental properties of dilute magnetic semiconductors using scanning tunneling microscopy (STM) and a relatively new technique, spin-polarized STM (SP-STM). SP-STM has tremendous potential to shed light on magnetic properties at atomic length scales. Understanding the details of the behaviour of spin and charge in dilute magnetic semiconductors might point the way towards making spintronic technology viable. This integrated project will capitalize on the excitement in the field of nanoscience and nanotechnology to attract middle and high school students to the sciences. The proposed outreach activities in the project are geared towards finding effective methods of decreasing the substantially large gender-gap in physics and engineering. Technical Abstract Unexpected phases and interesting phenomena are the hallmarks of systems involving interacting quantum spins. So it is with magnetic semiconductors, with recent reports of spin Coulomb drag, spin-torque effect, and a strong potential for applications in spintronic devices, leading the way to what promises to be an exciting new field. The goal of this Faculty Early Career project is to explore the fundamental properties of dilute magnetic semiconductors at the nanoscale using low temperature scanning tunneling spectroscopy and a relatively new technique, spin-polarized STM (SP-STM). SP-STM studies on these spintronic materials will shed light on important basic physics as well as materials related issues such as: (a) effective length scales of spin-spin interactions and magnetic domains, (b) how short range interactions lead to long range order, c) effect of clusters/precipitates on magnetic order and (d) how electronic and magnetic properties change with dimensionality. The education and outreach components of this proposal are strongly intertwined with the research goals of the project. A recurring theme in all outreach programs will be to generate excitement for physics and technology by exposure to recent advances in nanoscale science and potential for future applications.