Indirect Excitons

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NON-TECHNICAL ABSTRACTThis 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 quasi-particles 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 in high magnetic fields. The specific parameters of indirect excitons allow the realization of the high magnetic field regime in the lab. 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 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 and increase of fundamental understanding of the optical and electronic properties of materials.TECHNICAL ABSTRACTThis individual investigator award supports a project directed towards experimental studies of cold indirect excitons in coupled quantum well semiconductor structures. Indirect excitons are formed by electrons and holes confined in different quantum well layers. Due to their long lifetime, indirect excitons can cool below the temperature of quantum degeneracy. This gives an opportunity to study cold excitons. Due to their long lifetime, indirect excitons can travel over large distances before recombination. This gives an opportunity to study exciton transport. Furthermore, indirect excitons are dipoles and their energy can be controlled by voltage. This gives an opportunity to create a variety of potential landscapes for indirect excitons and use them as a tool for studying cold excitons ? cold composite bosons in materials. Studies include exciton transport and pattern formation in high magnetic fields. The specific parameters of indirect excitons allow the realization of the high magnetic field regime in the lab. The research is performed by students and is integrated with education. The potential impact of the project is in development of knowledge in condensed matter physics and increase of fundamental understanding of optical and electronic properties of materials.