Spin-1/2 magnetic impurity in a two-dimensional magnetic system close to a quantum critical point

[摘要] We consider a magnetic impurity in a spin liquid state of a magnetic system which is close to the quantum phase transition to the magnetically ordered state. There is similarity between this problem and the Kondo problem. We derive the impurity Green's function, consider renormalizations of the magnetic moments of the impurity, calculate critical indexes for the magnetic susceptibilities, and finally consider specific heat and magnetic interaction of two impurities.

[关键词] 2-DIMENSIONAL HEISENBERG-ANTIFERROMAGNET;TEMPERATURES;EXPANSIONS;PHASES;SPINS;MODEL