Indirect Excitons

University Of California-San Diego, La Jolla CA

Investigators

Abstract

****NON-TECHNICAL ABSTRACT**** This individual investigator award supports a project directed towards experimental studies of fundamental optical and electronic properties of structures made of thin layers of semiconductors. A special design of the structures on a length scale of a billionth part of a meter allows the creation of new entities called indirect excitons. The indirect excitons are unique because they can be cooled down to ultralow temperatures. Furthermore, the indirect excitons are also unique because they can be electronically controlled like electrons in electronic devices and can shine optical signals that electrons cannot do by themselves. The project is directed towards increasing our understanding of the physics of ultracold indirect excitons. In particular it will address the transport and optical properties of the indirect excitons. The understanding gained through this research may lead to the exciting possibility of developing advanced devices that make use of electronic as well as optical properties, i.e. optoelectronic devices. The students involved with this project will have the opportunity to perform exploratory research on the cutting edge of contemporary physics. The potential impact of the project is in development of knowledge in condensed matter physics, increase of fundamental understanding of the optical and electronic properties of materials, and in development of materials control. ****TECHNICAL ABSTRACT**** This individual investigator award supports a project directed towards experimental studies of ultracold gases of indirect excitons in coupled quantum well, semiconductor structures. Excitons are composite bosons. Due to their long lifetime and high cooling rate, the indirect excitons can be cooled below the temperature of quantum degeneracy. Furthermore, the indirect excitons have a built-in dipole moment and their energy can be controlled by an applied voltage. This allows creating in-plane potential profiles for indirect excitons by the voltage pattern. Studies will include exciton transport through various potential profiles and as well as exciton pattern formation and spontaneous coherence at ultralow temperatures. The research will be performed by students and will be integrated with education. The potential impact of the project is in development of knowledge in condensed matter physics, increase of fundamental understanding of the optical and electronic phenomena of materials, and in development of materials control.