Exact solution of a coupled spin-electron linear chain composed of localized Ising spins and mobile electrons

Exact solution of a coupled spin-electron linear chain composed of localized Ising spins and mobile electrons is found. The investigated spin-electron model is exactly solvable by the use of a transfer-matrix method after tracing out the degrees of freedom of mobile electrons delocalized over a couple of interstitial (decorating) sites. The exact ground-state phase diagram reveals an existence of five phases with different number of mobile electrons per unit cell, two of which are ferromagnetic, two are paramagnetic and one is antiferromagnetic. We have studied in particular the dependencies of compressibility and specific heat on temperature and electron density.