2006/07/31 by E. Boulat, Pankaj Mehta, P. Mehta +6 · 1 citation
Materials Science · Physics and Astronomy · #Condensed matter physics #Debye model #Drag #Phonon #Phonon drag #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Scattering #Spin (aerodynamics) #Thermal conductivity #Thermal properties of materials #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.76.214411
published as Phys. Rev. B 76, 214411 (2007) · revised version, 8 pages, 3 figures, added appendix
arxiv created 2007/10/15 · openalex publication_date 2007/12/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
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 (\ensuremathκmag) can be positive or negative and can exhibit an activated or antiactivated behavior. In most regimes, \ensuremathκmag 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 \ensuremathκmag∕\ensuremathκph of the magnetic and phononic contributions to the heat conductivity.