From quantum criticality to enhanced thermopower in strongly correlated layered cobalt oxide

Abstract

We report on susceptibility measurements in the strongly correlated layered cobalt oxide [BiBa0.66K0.36O2]CoO2, which demonstrate the existence of a magnetic quantum critical point (QCP) governing the electronic properties. The investigated low frequency susceptibility displays a scaling behavior with both the temperature T and the magnetic field B ranging from the high-T non-Fermi liquid down to the low-T Fermi liquid. Whereas the inferred scaling form can be discussed within the standard framework of the quantum critical phenomena, the determined critical exponents suggest an unconventional magnetic QCP of a potentially generic type. Accordingly, these quantum critical fluctuations account for the anomalous logarithmic temperature dependence of the thermopower. This result allows us to conjecture that quantum criticality can be an efficient source of enhanced thermopower.

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Cited by in corpus (8)

• Crossover from itinerant to localized states in the thermoelectric oxide [Ca${}_2$CoO${}_3$]${}_{0.62}$[CoO${}_2$]
• Magnetic field dependent specific heat and enhanced Wilson ratio in strongly correlated layered cobalt oxide
• Thermoelectric transport in the layered Ca${}_3$Co${}_{4-x}$Rh${}_x$O${}_9$ single crystals
• Thermoelectric signature of quantum critical phase in a doped spin liquid candidate
• Enhanced Seebeck coefficient through the magnetic fluctuations in Sr${}_2$Ru${}_{1-x}{M}_x$O${}_4$ ($M=$ Co, Mn)
• Strongly correlated Fermi systems as a new state of matter
• ω/T scaling of the optical conductivity in strongly correlated layered cobalt oxide
• Scaling behavior of the thermopower of the archetypical heavy-fermion metal $\mathrm{YbR}{\mathrm{h}}_2\mathrm{S}{\mathrm{i}}_2$