Abstract
Heat and charge transport were used to probe the magnetic field-tuned quantum critical point in the heavy-fermion metal . A comparison of electrical and thermal resistivities reveals three characteristic energy scales. A Fermi-liquid regime is observed below , with both transport coefficients diverging in parallel and as , the critical field. The characteristic temperature of antiferromagnetic spin fluctuations, , is tuned to a minimum but finite value at , which coincides with the end of the -linear regime in the electrical resistivity. A third temperature scale, , signals the formation of quasiparticles, as fermions of charge obeying the Wiedemann-Franz law. Unlike , it remains finite at , so that the integrity of quasiparticles is preserved, even though the standard signature of Fermi-liquid theory fails.
- Received 7 May 2004
DOI:https://doi.org/10.1103/PhysRevLett.97.106606
©2006 American Physical Society