Histogram Monte Carlo study of multicritical behavior in the hexagonal easy-axis Heisenberg antiferromagnet

The results of a detailed histogram Monte-Carlo study of critical-fluctuation effects on the magnetic-field temperature phase diagram associated with the hexagonal Heisenberg antiferromagnet with weak axial anisotropy are reported. The multiphase point where three lines of continuous transitions merge at the spin-flop boundary exhibits a structure consistent with scaling theory but without the usual umbilicus as found in the case of a bicritical point.Comment: 7 pages (RevTex 3.0), 1 figure available upon request, CRPS-93-1

A practical first-principles band-theory approach to the study of correlated materials

71.10.-w Theories and models of many-electron systems, 71.15.Mb Density functional theory, local density approximation, gradient and other corrections, 71.28.+d Narrow-band systems; intermediate-valence solids, 75.10.-b General theory and models of magnetic ordering,