Abstract
We investigate the phase transitions in two-legs ladder systems in the incommensurate phase, for which the gap is destroyed by a magnetic field and the ladder is not yet totally saturated . We compute quantitatively the correlation functions as a function of the magnetic field for an isolated strong-coupling ladder and use it to study the phase transition occurring in a three-dimensional array of antiferromagnetically coupled ladders. The three-dimensional ordering is in the universality class of Bose condensation of hard-core bosons. We compute the critical temperature as well as various physical quantities such as the NMR relaxations rate. has an unusual camel-like shape with a local minimum at and behaves as for . We discuss the experimental consequences for compounds such as .
- Received 19 October 1998
DOI:https://doi.org/10.1103/PhysRevB.59.11398
©1999 American Physical Society