Anderson localization of spinons in a spin-1/2 antiferromagnetic Heisenberg chain
arXiv:1208.3803
Abstract
Anderson localization is a general phenomenon of wave physics, which stems from the interference between multiple scattering paths1,2. It was originally proposed for electrons in a crystal, but later was also observed for light3-5, microwaves6, ultrasound7,8, and ultracold atoms9-12. Actually, in a crystal, besides electrons there may exist other quasiparticles such as magnons and spinons. However the search for Anderson localization of these magnetic excitations is rare so far. Here we report the first observation of spinon localization in copper benzoate, an ideal compound of spin-1/2 antiferromagnetic Heisenberg chain, by ultra-low-temperature specific heat and thermal conductivity measurements. We find that while the spinon specific heat Cs displays linear temperature dependence down to 50 mK, the spinons thermal conductivity ks only manifests the linear temperature dependence down to 300 mK. Below 300 mK, ks/T decreases rapidly and vanishes at about 100 mK, which is a clear evidence for Anderson localization. Our finding opens a new window for studying such a fundamental phenomenon in condensed matter physics.
17 pages, including 4 figures
References in corpus (5)
- Direct observation of Anderson localization of matter-waves in a controlled disorder
- Localization of ultrasound in a three-dimensional elastic network
- Heat conduction in low-dimensional quantum magnets
- Magnetothermal transport in the spin-1/2 chains of copper pyrazine dinitrate
- The Origin of Anomalous Low-Temperature Downturns in the Thermal Conductivity of Cuprates