University of Vermont

Theoretical Condensed Matter Physics

Many of the complex solids currently under intensive theoretical and experimental study have common attributes. High Tc superconductors, fullerene-based materials, and colossal magnetoresistive manganites all feature electronic and vibrational degeneracies that are a consequence of the spatial symmetries of the crystal structure. These systems typically have multiple electronic and structural phases competing at low temperatures. And there is ample evidence that the electron-phonon interaction and the resulting polaron quasiparticles play an important role in shaping many of the physical properties of these materials.

These observations serve as motivation for the theoretical study of the effects of generalized electron-phonon coupling in multiband systems. Novel multicomponent polarons--"vector polarons"-- have been found to exist in such systems. They are mathematically related to soliton solutions of coupled non-linear Schrodinger equations that have been previously studied in many different contexts such as nonlinear optics (propagation of light in birefringent optical fibers) and atomic physics (spinor Bose-Einstein condensation).

Vector polarons, together with a many-electron Q-ball-like excited state called a Jahn-Teller soliton, serve as examples that systems containing electronic and vibrational degeneracy can support novel states through local Jahn-Teller interactions.

  • D.P. Clougherty, Polarons and Solitons in Jahn-Teller Systems, (invited paper) J. Mol. Struct. 838, 203 (2007).
  • D.P. Clougherty and C.A. Foell, Vector Polarons in a Degenerate Electron System, Phys. Rev. B 70, 052301 (2004).
  • D.P. Clougherty, Jah\n-Teller Solitons, Structural Phase Transitions and Phase Separation, Phys. Rev. Lett. 96, 045703 (2006).
  • Last modified January 04 2019 01:00 PM

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