Seminars & Lectures
| * TITLE | Violation of Wiedemann-Franz law at the Kondo breakdown quantum critical point | ||||||
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| * DATE / TIME | 2008-11-07, 3:00 - 4:00 p.m. | ||||||
| * PLACE | APCTP Seoul Branch Office | ||||||
| * ABSTRACT | |||||||
| We study both electrical and thermal transport near one heavy-fermion quantum critical point (QCP), identified with breakdown of Kondo effect as an orbital selective Mott transition. Based on the Eliashberg framework taking both hybridization and gauge fluctuations into account on equal footing, we show that the electrical conductivity is contributed mainly from conduction electrons while the thermal conductivity is given by both conduction electrons and localized fermions (spinons), scattered with dynamical exponent $z = 3$ hybridization fluctuations. This scattering mechanism gives rise to temperature quasi-linear electrical and thermal resistivities near the Kondo breakdown QCP. The characteristic feature of the Kondo breakdown scenario turns out to be emergence of additional entropy carriers, that is, spinon excitations. As a result, we find that the Wiedemann-Franz ratio should be larger than the value of Fermi liquid in the low temperature limit, discriminating the Kondo breakdown scenario from the Hertz-Moriya-Millis framework. |
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