Moessbauer U- centers as tools for studying the Bose condensation in semiconductors

It is shown that the Moessbauer two-electron centers with negative correlation energy are efficient tools for studying the processes of Bose condensation of electron pairs in superconducting phase transition. The corresponding probes are sensitive to two-electron processes and determine their high sensitivity to a variation in the electron density at the phase transition. It is shown that a variation in the electron density in the case of a phase transition depends on the critical temperature Tc and is different for different sublattices.