Direction dependent free energy singularity of the asymmetric six-vertex model

Abstract

The transition from the ordered commensurate phase to the incommensurate gaussian phase of the antiferroelectric asymmetric six-vertex model is investigated by keeping the temperature constant below the roughening point and varying the external fields $(h,v)$. In the $(h,v)$ plane, the phase boundary is approached along straight lines $\delta v=k\delta h$, where $(\delta h,\delta v)$ measures the displacement from the phase boundary. It is found that the free energy singularity displays the exponent 3/2 typical of the Pokrovski-Talapov transition $\delta f\sim const(\delta h{)}^{3/2}$ for any direction other than the tangential one. In the latter case $\delta f$ shows a discontinuity in the third derivative.

18 pages, Latex, 1 figure, minor corrections and two references changed

References in corpus (3)

• Phase diagram of the non-hermitean asymmetric XXZ spin chain
• Finite-size scaling and the toroidal partition function of the critical asymmetric six-vertex model
• The free energy singularity of the asymmetric 6--vertex model and the excitations of the asymmetric XXZ chain