Inhomogeneous ground state and the coexistence of two length scales near phase transitions in real solids
Electro-Engineering Institute - 197376 St. Petersburg, Russia
2 Theoretische Physik III, Ruhr-Universität - 44780 Bochum, Germany
Accepted: 22 November 1995
Real crystals almost unavoidably contain a finite density of dislocations. We show that this generic type of long-range correlated disorder leads to a breakdown of the conventional scenario of critical behavior and standard renormalization group techniques based on the existence of a simple, homogeneous ground state. This breakdown is due to the appearance of an inhomogeneous ground state that changes the character of the phase transition to that of a percolative phenomenon. This scenario leads to a natural explanation for the appearance of two length scales in recent high resolution small-angle scattering experiments near magnetic and structural phase transitions.
PACS: 64.60.Ak – Renormalization-group, fractal, and percolation studies of phase transitions / 75.10.Nr – Spin-glass and other random models
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