Issue
EPL
Volume 82, Number 6, June 2008
Article Number 67008
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/82/67008
Published online 10 June 2008
EPL, 82 (2008) 67008
DOI: 10.1209/0295-5075/82/67008

The valence bond glass phase

M. Tarzia and G. Biroli

Institut de Physique Théorique, Orme des Merisiers

biroli@cea.fr

received 19 February 2008; accepted in final form 4 May 2008; published June 2008
published online 10 June 2008

Abstract
We show that a new glassy phase can emerge in the presence of strong magnetic frustration and quantum fluctuations. It is a valence bond glass (VBG). We study its properties solving the Hubbard-Heisenberg model on a Bethe lattice within the large-N limit introduced by Affleck and Marston. We work out the phase diagram that contains Fermi liquid, dimer and valence bond glass phases. This new glassy phase has no electronic or spin gap (although a pseudo-gap is observed), it is characterized by long-range critical valence bond correlations and is not related to any magnetic ordering. As a consequence, it is quite different from both valence bond crystals and spin glasses.

PACS
71.10.Fd - Lattice fermion models (Hubbard model, etc.).
75.50.Lk - Spin glasses and other random magnets.
64.70.P- - Glass transitions of specific systems.

© EPLA 2008