1,153 research outputs found
Transport in dimerized and frustrated spin systems
We analyze the Drude weight for both spin and thermal transport of
one-dimensional spin-1/2 systems by means of exact diagonalization at finite
temperatures. While the Drude weights are non-zero for finite systems, we find
indications of a vanishing of the Drude weights in the thermodynamic limit for
non-integrable models implying normal transport behavior.Comment: 2 pages, 1 figure. Proceedings of the ICM 2003, Rom
Transport in quasi one-dimensional spin-1/2 systems
We present numerical results for the spin and thermal conductivity of
one-dimensional (1D) quantum spin systems. We contrast the properties of
integrable models such as the spin-1/2 XXZ chain against nonintegrable ones
such as frustrated and dimerized chains. The thermal conductivity of the XXZ
chain is ballistic at finite temperatures, while in the nonintegrable models,
this quantity is argued to vanish. For the case of frustrated and dimerized
chains, we discuss the frequency dependence of the transport coefficients.
Finally, we give an overview over related theoretical work on intrinsic and
extrinsic scattering mechanisms of quasi-1D spin systems.Comment: 11 pages, 7 figure
Comment on "Anomalous Thermal Conductivity of Frustrated Heisenberg Spin Chains and Ladders"
In a recent letter [Phys. Rev. Lett. 89, 156603 (2002); cond-mat/0201300],
Alvarez and Gros have numerically analyzed the Drude weight for thermal
transport in spin ladders and frustrated chains of up to 14 sites and have
proposed that it remains finite in the thermodynamic limit. In this comment, we
argue that this conclusion cannot be sustained if the finite-size analysis is
taken to larger system sizes.Comment: One page REVTeX4, 1 figure. Published version (minor changes
- …