This award supports theoretical research and education to develop an effective electrodynamics for charge carriers in graphene, Weyl semimetals, topological insulators, and related unconventional materials.
Materials have been identified for which the breaking of continuous translational symmetry by the lattice results in pseudspin-orbit-coupled band dynamics that is qualitatively different from the dynamics of charge carriers in free space. Specific materials include graphene and topological insulators. The PI will develop a general theory for the electrodynamics of such unconventional systems that is expected to be markedly different from ordinary electrodynamics in macroscopic media. Combining quantum field theory and group-theoretical methods, the PI will establish a Lagrangian description, similar to the Lagrangian of quantum electrodynamics, from which he can derive the equations of motion for the co-operative dynamics of charges, pseudospins, spins, and fields. New electromagnetic phenomena reflecting the rich physics of these material systems may be discovered. The findings will predict material behavior for a wide variety of experiments using electric and magnetic fields as probes. The research will provide insights into how electric charges, pseudospins, and spins interact with electric and magnetic fields. The results of this project may eventually enable electromagnetic control of charges and spins in devices based on unconventional materials.
This award also supports educational and outreach activities, including public lectures and involvement with the department's Physics Olympics and Haunted Physics House.
NONTECHNICAL SUMMARY
This award supports theoretical research and education to develop a theoretical description of the dynamics of electrons in unconventional materials like graphene in electric and magnetic fields. The electrons in familiar electrical conductors act very much like electrons in empty space; their interactions with the atoms of the material for the most part can be modeled by adjusting their "effective" masses up or down from the true mass of an electron in vacuum. Similarly, the interactions of atoms and electrons in the presence of applied electric and magnetic fields in traditional materials lead to adjustments of the effective values of the fields. However, new materials have been discovered in which the electrons behave qualitatively unlike electrons in vacuum; in fact, the electrons look in some ways more like slow-moving light. Two examples of the new types of materials are graphene and topological insulators; graphene consists of a single atomic layer of graphite or ordinary pencil lead, while topological insulators are materials that are electrical insulators in their interiors but which support electrical currents on their surfaces. To replace the nineteenth-century equations used to describe electric and magnetic interactions in conventional matter, the PI will develop a new theory to describe the electrons in these new materials.
A theory of electrodynamics in these new media is a prerequisite to the design of new electronic devices that take advantage of their unusual properties. This award also supports educational and outreach activities, including public lectures and involvement with the department's Physics Olympics and Haunted Physics House.
