Crossover temperature of the spin-1/2 XXZ chain with an impurity

23rd International Conference on Integrable Systems and Quantum Symmetries

Yahagi, Ryoko^1 ; Sato, Jun^2 ; Deguchi, Tetsuo^3

Department of Physics, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo

112-8610, Japan^1

Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo

153-8904, Japan^2

Department of Physics, Faculty of Core Research, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo

112-8610, Japan^3

关键词: Analytic expressions;    Bethe ansatz method;    Crossover behavior;    Crossover temperature;    High-temperature regime;    Low temperatures;    Periodic chains;    Quantum spin chains;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/670/1/012054/pdf
DOI  :  10.1088/1742-6596/670/1/012054

来源: IOP

【 摘 要 】

We study exactly the effect of an impurity in the interacting quantum spin chain at low temperature by solving the integrable spin-1/2 XXZ periodic chain with an impurity through the algebraic and thermal Bethe ansatz methods. In particular, we investigate how the crossover temperature for the impurity specific heat depends on the impurity parameter, i.e. the coupling of the impurity to other spins, and show that it is consistent with the analytic expression that is obtained by setting the impurity susceptibility to be proportional to the inverse of the crossover temperature. In the model, two types of crossover behavior appear: one from the high-temperature regime to the low-temperature Kondo regime and another from the N-site homogeneous chain to the (N - 1)-site chain with a decoupled free impurity spin, with respect to the temperature and the impurity parameter, respectively.