53 research outputs found
Thermal Conductivity in the Bose-Einstein Condensed State of Triplons in the Bond-Alternating Spin-Chain System Pb2V3O9
In order to clarify the origin of the enhancement of the thermal conductivity
in the Bose-Einstein Condensed (BEC) state of field-induced triplons, we have
measured the thermal conductivity along the [101] direction parallel to
spin-chains, , and perpendicular to spin-chains,
, of the S=1/2 bond-alternating spin-chain system Pb2V3O9
in magnetic fields up to 14 T. With increasing field at 3 K, it has been found
that both and are suppressed in the
gapped normal state in low fields. In the BEC state of field-induced triplons
in high fields, on the other hand, is enhanced with
increasing field, while is suppressed. That is, the
thermal conductivity along the direction, where the magnetic interaction is
strong, is markedly enhanced in the BEC state. Accordingly, our results suggest
that the enhancement of in the BEC state is caused by the
enhancement of the thermal conductivity due to triplons on the basis of the
two-fluid model, as in the case of the superfluid state of liquid 4He.Comment: 5 pages, 3 figure
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