Disorder-Driven Metal-Insulator Transitions in Deformable Lattices
Abstract
We show that, in the presence of a deformable lattice potential, the nature of the disorder-driven metal-insulator transition is fundamentally changed with respect to the noninteracting (Anderson) scenario. For strong disorder, even a modest electron-phonon interaction is found to dramatically renormalize the random potential, opening a mobility gap at the Fermi energy. This process, which reflects disorder-enhanced polaron formation, is here given a microscopic basis by treating the lattice deformations and Anderson localization effects on the same footing. We identify an intermediate "bad insulator" transport regime which displays resistivity values exceeding the Mott-Ioffe-Regel limit and with a negative temperature coefficient, as often observed in strongly disordered metals. Our calculations reveal that this behavior originates from significant temperature-induced rearrangements of electronic states due to enhanced interaction effects close to the disorder-driven metal-insulator transition.
- Publication:
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Physical Review Letters
- Pub Date:
- January 2017
- DOI:
- 10.1103/PhysRevLett.118.036602
- arXiv:
- arXiv:1604.07816
- Bibcode:
- 2017PhRvL.118c6602D
- Keywords:
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- Condensed Matter - Disordered Systems and Neural Networks
- E-Print:
- 5 pages, 4 figures, revised version accepted in Phys. Rev. Lett