Divergence of the grüneisen ratio at quantum critical points in heavy fermion metals.
Phys Rev Lett
; 91(6): 066405, 2003 Aug 08.
Article
en En
| MEDLINE
| ID: mdl-12935093
ABSTRACT
We present low-temperature volume thermal expansion, beta, and specific heat, C, measurements on high-quality single crystals of CeNi2Ge2 and YbRh2(Si0.95Ge0.05)(2) which are located very near to quantum critical points. For both systems, beta shows a more singular temperature dependence than C, and thus the Grüneisen ratio Gamma proportional to beta/C diverges as T-->0. For CeNi2Ge2, our results are in accordance with the spin-density wave (SDW) scenario for three-dimensional critical spin fluctuations. By contrast, the observed singularity in YbRh2(Si0.95Ge0.05)(2) cannot be explained by the itinerant SDW theory but is qualitatively consistent with a locally quantum critical picture.
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MEDLINE
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En
Revista:
Phys Rev Lett
Año:
2003
Tipo del documento:
Article
País de afiliación:
Alemania