FisMat2017 - Submission - View

Abstract's title: Disorder-Driven Metal-Insulator Transitions in Deformable Lattices
Submitting author: Sergio Ciuchi
Affiliation: University of L'Aquila / CNR-ISC Rome
Affiliation Address: Department of Physical and Chemical Sciences University of L'Aquila and ISC-CNR Rome
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Domenico Di Sante (Institute of Physics and Astrophysics, University of Würzburg, Germany/CNR_SPIN L'Aquila Italy), Vladimir Dobrosavljevic ́ (Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA), Simone Fratini (Institut Néel-CNRS and Université Grenoble Alpes, Grenoble, France)

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 [1]. 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.
[1] Domenico Di Sante, Simone Fratini, Vladimir Dobrosavljević, and Sergio Ciuchi Phys. Rev. Lett 118 036602 (2017)