Spin Ordering and Transport in Correlated Electronic and Atomic Systems

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

TECHNICAL SUMMARY: This award supports theoretical research and education on spin ordering and transport in correlated electronic and atomic systems. The PI will investigate problems in the collective spin physics of correlated electron materials and Bose-Einstein condensates of atoms with nonzero spin. The research is divided into three subfields: spin transport phenomena related to the new class of materials called ''topological insulators''; quantum effects on the phase ordering and coherent dynamics of spinor Bose condensates; applications of quantum information ideas to improved characterization and simulation of frustrated magnets. In each of these subfields, the research builds on the PI?s work performed under prior NSF support. The key elements in the first research area are to understand how correlation physics is modified in a topological insulator and to describe three dimensional topological insulators in greater depth. In the second area, the PI studies effects of topological defects and dipolar interactions on the quantum theory of Bose condensates with spin, as these are believed to be essential for the interpretation of experiments. In the third area, the research tests specific proposals for DMRG-like algorithms in dimension greater than one on frustrated magnetic models of current experimental interest. The work has broader impact beyond the specific research investigations including education and relevance to emerging device technologies. The work on spin transport in solids is currently of great interest in the applied semiconductor community, and devices using the quantum nature of electron spin are in development. The research is relevant to ideas of future use of spinor Bose condensates as ultrasensitive magnetic field detectors with spatial resolution finer than in the best existing devices with applications beyond MRI devices. Scientifically, improved algorithms to find ground states of local Hamiltonians are important in many areas of physics. This award has educational befits, the first being support of graduate students who will use the research as the basis for the Ph.D. Dissertation. The work influences the efforts of the PI in course development and undergraduate student research supervision within the university. With this award, the PI will continue development of on line educational materials with Lawrence Hall of Science as the major component of the outreach program, in conjunction with annual public lectures or panels for high school students. NONTECHNICAL SUMMARY: This award supports research and education on the recently discovered phenomena of electrical signals that are not associated with moving electrical charges, but rather associated with the seeming intrinsic rotation or spin that electron possess and the way groups of electrons transfer spin spatially. The phenomena are not unrelated to magnetism which also is connected to the intrinsic electron spin. The phenomena have been observed, but the theoretical explanation is less clear and the research seeks to clarify physical mechanisms and thereby add to the ability to control and utilize the phenomenon in device technology. Eventually, this may be the basis of electronic logic devices that are orders of magnitude faster and more efficient that the current transistor technology based on charge movement and charge accumulation. The work has broader impact beyond the specific research investigations including education and relevance to emerging device technologies. The work on spin transport in solids is currently of great interest in the applied semiconductor community, and devices using the quantum nature of electron spin are in development. The research is relevant to ideas of future use of spinor Bose condensates as ultrasensitive magnetic field detectors with spatial resolution finer than in the best existing devices with applications beyond MRI devices. Scientifically, improved algorithms are important in many areas of physics. This award has educational befits, the first being support of graduate students who will use the research as the basis for the Ph.D. Dissertation. The work influences the efforts of the PI in course development and undergraduate student research supervision within the university. With this award, the PI will continue development of on line educational materials with Lawrence Hall of Science as the major component of the outreach program, in conjunction with annual public lectures or panels for high school students.