Unusually Thick Metal-Insulator Domain Walls Around the Mott Point

Many Mott systems feature a first-order metal-insulator transition at finite temperatures, with an associated phase coexistence region displaying inhomogeneities and local phase separation. Here one typically finds "bubbles" or domains of the respective phases, which are separated by surprisingly thick, or fat, domain walls, as revealed both by imaging experiments and recent theoretical modeling. To gain insight into this unexpected behavior, we perform a systematic model study of the structure of such metal-insulator domain walls around the Mott point, within the dynamical mean-field theory framework. Our study reveals that a mechanism producing such "fat" domain walls can be traced to strong magnetic frustration, which is expected to be a robust feature of "spin-liquid" Mott systems.