Anomalous properties and coexistence of antiferromagnetism and superconductivity near a quantum critical point in rare-e
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ISORDER, AND PHASE TRANSITION IN CONDENSED SYSTEM
Anomalous Properties and Coexistence of Antiferromagnetism and Superconductivity near a Quantum Critical Point in RareEarth Intermetallides1 V. V. Val’kova,b,* and A. O. Zlotnikova a
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, 660036 Russia * email: [email protected] b Siberian State Aerospace University, Krasnoyarsk, 660014 Russia Received July 2, 2012
Abstract—Mechanisms of the appearance of anomalous properties experimentally observed at the transition through the quantum critical point in rareearth intermetallides have been studied. Quantum phase transi tions are induced by the external pressure and are manifested as the destruction of the longrange antiferro magnetic order at zero temperature. The suppression of the longrange order is accompanied by an increase in the area of the Fermi surface, and the effective electron mass is strongly renormalized near the quantum critical point. It has been shown that such a renormalization is due to the reconstruction of the quasiparticle band, which is responsible for the formation of heavy fermions. It has been established that these features hold when the coexistence phase of antiferromagnetism and superconductivity is implemented near the quantum critical point. DOI: 10.1134/S1063776113050129 11.
The destruction of the longrange order at the quantum phase transition is caused by an increase in quantum fluctuations whose intensity is governed by a control parameter (e.g., pressure) [1, 2]. The applica tion of hydrostatic pressure in cerium intermetallides at temperatures below the Néel temperature sup presses the longrange antiferromagnetic order, lead ing to its sharp destruction at the quantum phase tran sition. In this case, a transition to a superconducting state is observed near the quantum critical point. The CeRhIn5 compound is of particular interest in recent years because the coexistence phase of super conductivity and antiferromagnetism, which is homo geneous at the microscopic scale, is implemented in it [3]. The role of cerium ions and itinerant p states of indium atoms is significant in the formation of the electronic structure of this compound [4]. It was shown that hybridization mixing is implemented between 4f Ce states and p In states [5]. These facts underlie the assumption that the periodic Anderson model can be used for the qualitative description of features of the lowenergy spectrum of Fermi excita tions in CeRhIn5. In this description, it is accepted that the subsystem of 4f electrons is responsible for the formation of both the antiferromagnetic order and Cooper instability. 1 The article is based on a preliminary report delivered at the 36th
Conference on LowTemperature Physics (St. Petersburg, July 2–6, 2012).
The first approach to the problem of quantum crit ical points is based on the generalization of the fluctu ation theory of phase transitions to the case of zero temperature [6]. It was shown in [7] that quantum fluctuati
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