Abstract
The electrical and thermal Hall conductivities of the cuprate superconductor and , were measured in a magnetic field up to 35 T, at a hole concentration (doping) . In the limit, we find that the Wiedemann-Franz law, , is satisfied for fields immediately above the vortex-melting field . This rules out the existence of a vortex liquid at and it puts a clear constraint on the nature of the normal state in underdoped cuprates, in a region of the doping phase diagram where charge-density-wave order is known to exist. As the temperature is raised, the Lorenz ratio, , decreases rapidly, indicating that strong small- scattering processes are involved.
1 More- Received 19 November 2015
- Revised 29 January 2016
DOI:https://doi.org/10.1103/PhysRevB.93.064513
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