Study of ultrasonic attenuation for the Kondo and magnetic effects in heavy fermion systems

摘要: The heavy fermion (HF) systems draw considerable attention due to their cooperative phenomena and anomalous properties arising out of the huge effective mass. A system is described by a model Hamiltonian consisting Kondo lattice in addition Heisenberg-type spin-spin interaction among localised electrons. treated mean-field approximation find singlet parameter λ short-ranged f-electron correlation Γ. In order investigate ultrasonic absorption system, we consider phonon with bare f-electrons, coupling singlets. Further, considered harmonic approximation. Green’s function calculated closed form. imaginary part self-energy describes attenuation for HF systems. clearly displays region separated state at low temperatures. transition temperature are located dips temperature-dependent attenuation. dependence investigated varying physical parameters wave frequency, experimental observations explained on basis calculations.