Colossal enhancement of upper critical fields in noncentrosymmetric heavy fermion superconductors near quantum criticality: CeRhSi3 and CeIrSi3.
Strong-coupling effects on the upper critical fields Hc2 along the c axis in the noncentrosymmetric heavy fermion superconductors near quantum criticality CeRhSi3 and CeIrSi3 are examined. For sufficiently large spin-orbit interactions due to the lack of inversion symmetry, Hc2 is mainly determined by the orbital depairing effects. From microscopic calculations taking into account the strong spin fluctuations, we show that Hc2 is extremely enhanced as the system approaches the quantum critical point, resulting in Hc2 approximately 30 T even in the case of a low transition temperature Tc(H = 0) approximately 1 K, which explains well the huge Hc2 observed in the recent experiments.
Department of Physics, Kyoto University, Kyoto 606-8502, Japan. tada@scphys.kyoto-u.ac.jp
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Tada
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Kawakami
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Fujimoto