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arXiv · 1202.2753

Thermoelectric response near a quantum critical point of beta-YbAlB4 and YbRh2Si2: A comparative study

Y. Machida·K. Tomokuni·C. Ogura·K. Izawa·K. Kuga·S. Nakatsuji·G. Lapertot·G. Knebel·J. -P. Brison·J. Flouquet
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Abstract

The thermoelectric coefficients have been measured on the Yb-based heavy fermion compounds beta-YbAlB4 and YbRh2Si2 down to a very low temperature. We observe a striking difference in the behavior of the Seebeck coefficient, S in the vicinity of the Quantum Critical Point (QCP) in the two systems. As the critical field is approached, S/T enhances in beta-YbAlB4 but is drastically reduced in YbRh2Si2. While in the former system, the ratio of thermopower-to-specific heat remains constant, it drastically drops near the QCP in YbRh2Si2. In both systems, on the other hand, the Nernst coefficient shows a diverging behavior near the QCP. The results provide a new window to the way various energy scales of the system behave and eventually vanish near a QCP.

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Y. Machida, K. Tomokuni, C. Ogura, K. Izawa, K. Kuga, S. Nakatsuji, G. Lapertot, G. Knebel, J. -P. Brison, J. Flouquet. 2012-02-13. Thermoelectric response near a quantum critical point of beta-YbAlB4 and YbRh2Si2: A comparative study. https://doi.org/10.1103/physrevlett.109.156405

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