Low-temperature heat conductivity of ZnSe:Ni crystals: An unusually strong resonant change caused by phonon scattering from the anharmonic modes induced by charged impurities

An anomalously strong resonancelike change with a sharp minimum at a temperature of 15±1 K was observed for the heat conductivity of ZnSe:Ni crystals for the first time. The heat conductivity of one of the samples decreased by more than 200 times, as compared to its maximal value in pure ZnSe. A new phonon scattering mechanism including the A processes is suggested to interpret the unusual temperature dependence of heat conductivity. These are the umklapp processes accompanying the phonon scattering from the anharmonic modes induced by charged nickel impurities. As a result, the efficiency of A processes may be very high and comparable at 15 K to the efficiency of the U processes in ZnSe at a temperature of approximately 1000 K.