Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics
Effect of bulk magnetic field on critical Ising films
A. Drzewiński, Anna Maciołek, A. Ciach
Abstract
Two-dimensional Ising films $L\ifmmode\times\else\texttimes\fi{}\ensuremath{\infty}$ in a nonvanishing bulk magnetic field H are studied at the bulk critical temperature ${T}_{c}$ for two choices of surface fields (a) ${H}_{1}{=H}_{L}=0$ (ordinary transition), and (b) ${H}_{1}{=H}_{L}=\ensuremath{\infty}$ (normal transition) by the density-matrix renormalization-group method. Universal scaling functions for magnetization profiles, the excess magnetization $\ensuremath{\Gamma},$ the longitudinal correlation length ${\ensuremath{\xi}}_{\ensuremath{\Vert}},$ and for the analog of the solvation force ${f}_{\mathrm{solv}}$ are found and discussed. When ${H}_{1}=0$ the scaling function for ${f}_{\mathrm{solv}}$ has two symmetric minima at $y=\mathrm{sgn}(H)L|H{|}^{\ensuremath{\nu}/\ensuremath{\Delta}}\ensuremath{\approx}\ifmmode\pm\else\textpm\fi{}1$ with an amplitude at the minimum about 3.8 times the value at $H=0,$ the Casimir amplitude. For the normal transition the scaling function for ${f}_{\mathrm{solv}}$ has a single minimum near the continuation of the pseudocoexistence (capillary condensation) line, with an amplitude about 100 times the Casimir amplitude.