Optical Spectroscopy and Control of Many-Body Dynamics in Semiconductors in High Magnetic Fields

William Marsh Rice University, Houston TX

Investigators

Abstract

****Technical Abstract**** This project will probe and control non-equilibrium many-body dynamics in three prototypical low-dimensional semiconductors - quantum wells, graphene, and carbon nanotubes - using ultrafast optical spectroscopy in high magnetic fields. The optics facilities at the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, Florida, as well as the newly implemented mini-coil pulsed magnet system in the PI's laboratory at Rice University will be utilized. Various ultrafast optical and microspectroscopy techniques in magnetic fields will be employed to provide new insight into the states and dynamics of interacting and confined electrons in solids. Clarifying and answering the above-stated issues and questions will not only advance our understanding of carrier interactions in solids but also open up possibilities for new devices utilizing many-body effects. This project will train undergraduate and graduate students in cutting-edge techniques to produce the next generation of experts in optical spectroscopy, condensed matter physics, and nanoscienec. Furthermore, through the unique linkage with the PI's Partnerships for International Research and Education grant from the NSF, this project will provide an opportunity for alumni of the NanoJapan: Summer Nanotechnology Research Program for Undergraduates to further their research experience with a summer internship at the NHMFL. ****Non-Technical Abstract**** Modern crystal growth and nanofabrication technologies allow one to create artificial nanostructures with tailored properties. These structures provide an ideal laboratory in which to study fundamental physics problems in a highly controllable manner. This project will investigate how individual electrons communicate with each other and behave cooperatively in three prototypical nanostructures: semiconductor quantum wells, graphene, and carbon nanotubes. Short and intense laser pulses combined with high magnetic fields will be used; a high magnetic field provides a convenient knob for controlling electron dynamics through the magnetic quantization of the orbital and spin motions of electrons. Facilities at the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, Florida, as well as a pulsed high-field magnet system in the PI's laboratory at Rice University will be utilized. Specific questions to be addressed include: i) How do independent electron-hole pairs develop macroscopic coherence?; ii) How does a collective nature manifest itself in the quantum coherent dynamics of a two-dimensional electron gas?; and iii) How stable are one-dimensional excitons at quantum degenerate densities? Answering these questions will not only advance our understanding of carrier interactions in solids but also open up possibilities for new devices utilizing many-body effects. We will also train undergraduate and graduate students in cutting-edge techniques to produce the next generation of experts in optical spectroscopy, condensed matter physics, and nanoscience.