522 research outputs found
Gapless Magnetic and Quasiparticle Excitations due to the Coexistence of Antiferromagnetism and Superconductivity in CeRhIn : A study of In-NQR under Pressure
We report systematic measurements of ac-susceptibility,
nuclear-quadrupole-resonance spectrum, and nuclear-spin-lattice-relaxation time
() on the pressure ()- induced heavy-fermion (HF) superconductor
CeRhIn. The temperature () dependence of at = 1.6 GPa has
revealed that antiferromagnetism (AFM) and superconductivity (SC) coexist
microscopically, exhibiting the respective transition at K and
= 0.9 K. It is demonstrated that SC does not yield any trace of gap
opening in low-lying excitations below K, but K, followed by a = const law. These results point to the
unconventional characteristics of SC coexisting with AFM. We highlight that
both of the results deserve theoretical work on the gapless nature in low-lying
excitation spectrum due to the coexistence of AFM and SC and the lack of the
mean-field regime below K.Comment: 4pages,5figures,revised versio
Emergent states in heavy electron materials
We obtain the conditions necessary for the emergence of various low
temperature ordered states (local moment antiferromagnetism, unconventional
superconductivity, quantum criticality, and Landau Fermi liquid behavior) in
Kondo lattice materials by extending the two-fluid phenomenological theory of
heavy electron behavior to incorporate the concept of hybridization
effectiveness. We use this expanded framework to present a new phase digram and
consistent physical explanation and quantitative description of measured
emergent behaviors such as the pressure variation of the onset of local moment
antiferromagnetic ordering at T_N, the magnitude of the ordered moment, the
growth of superconductivity within that ordered state, the location of a
quantum critical point, and of a delocalization line in the
pressure/temperature phase diagram at which local moments have disappeared and
the heavy electron Fermi surface has grown to its maximum size. We apply our
model to CeRhIn_5 and a number of other heavy electron materials and find good
agreement with experiment.Comment: 20 pages, 8 figures, 1 tabl
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