Energy pseudogaps and structural transitions in metals

It is shown that a structural transition in a metal is associated with the opening of the energy pseudogap in the electronic spectrum in a low-temperature phase below the transition temperature. A relation between the magnitude of the energy pseudogap in the d-band of transition metals (at zero temperature) and the structural transition temperature is similar to a relation between the magnitude of the superconducting gap and the superconducting transition temperature in low-temperature and high-temperature superconductors. A relation between the magnitude of the energy pseudogap and the structural transition temperature in sp-metals is similar to a relation between the bandgap width (at zero temperature) and the metal-insulator transition temperature in semiconductors.