Scaling Theory of the Mott Transition and Breakdown of the Grueneisen Scaling Near a Finite-Temperature Critical End Point

摘要

We discuss a scaling theory of the lattice response in the vicinity of a finite-temperature critical end point. The thermal expansivity is shown to be more singular than the specific heat such that the Grueneisen ratio diverges as the critical point is approached, except for its immediate vicinity. More generally, we express the thermal expansivity in terms of a scaling function which we explicitly evaluate for the two-dimensional Ising universality class. Recent thermal expansivity measurements on the layered organic conductor κ-(BEDT-TTF)_2X close to the Mott transition are well described by our theory.