Theory of phase-separation dynamics in high-density electron–hole systems

The phase-separation dynamics in a high-density electron–hole (e–h) system is investigated theoretically to understand how the e–h liquid or droplet is formed spatiotemporally in a nonequilibrium situation. We stress two characteristic points of such dynamics: the finite-lifetime effect and the quantum nature. To clarify these separately, two types of theoretical framework are introduced: a spinodal-decomposition theory taking into account the finite lifetime of classical particles, and a quantum generalized Langevin theory derived from a microscopic e–h Hamiltonian coupled with a phonon reservoir.