arXiv:cond-mat/9708116 · Physical Review Letters
A New Disorder-Driven Roughening Transition of Charge-Density Waves and Flux-Line Lattices
Thorsten Emig A, Thomas Nattermann
Abstract
We study the competition between pinning of a charge-density wave by random distributed impurities and a periodic potential of the underlying crystal lattice. In $d\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3$ dimensions, we find for commensurate phases of order $p>{p}_{c}\ensuremath{\approx}6/\ensuremath{\pi}$ a disorder-driven continuous roughening transition from a ``flat'' phase with translational long-range order to a ``rough'' glassy phase with quasi-long-range order. Critical exponents are calculated in a double expansion in $\ensuremath{\mu}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}p}^{2}{/p}_{c}^{2}\ensuremath{-}1$ and $\ensuremath{\epsilon}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4\ensuremath{-}d$ and fulfill the scaling relations of random field models. Implications for flux-line lattices in high temperature superconductors are briefly discussed.