Heat transport properties of clean spin ladders coupled to phonons: Umklapp scattering and drag

Article

关键词: CONDUCTIVITY;    CONSERVATION;   

DOI  :  10.1103/PhysRevB.76.214411

来源: SCIE

【 摘 要 】

We study the low-temperature heat transport in clean two-leg spin-ladder compounds coupled to three-dimensional phonons. We argue that the very large heat conductivities observed in such systems can be traced back to the existence of approximate symmetries and corresponding weakly violated conservation laws of the effective (gapful) low-energy model, namely, pseudomomenta. Depending on the ratios of spin gaps and Debye energy and on the temperature, the magnetic contribution to the heat conductivity (kappa(mag)) can be positive or negative and can exhibit an activated or antiactivated behavior. In most regimes, kappa(mag) is dominated by the spin-phonon drag: the excitations of the two subsystems have almost the same drift velocity, and this allows for an estimate of the ratio kappa(mag)/kappa(ph) of the magnetic and phononic contributions to the heat conductivity.

【 授权许可】

Free