Strong-coupling theory of magnetic-exciton-mediated superconductivity in UPd${}_2$Al${}_3$

Abstract

There is compelling evidence from inelastic-neutron-scattering and tunneling experiments that the heavy-fermion superconductor UPd${}_2$Al${}_3$ can be understood as a dual system consisting of magnetic excitons, arising from crystal-field-split U${}^{4+}$ levels, coupled to delocalised f-electrons. We have computed the superconducting transition temperature and the mass renormalisation arising from a dual model with maximal spin anisotropy using a strong-coupling approach. We find an instability to two possible opposite-spin-pairing states with even- or odd-parity gap functions. Each has a line node perpendicular to the c-direction, in agreement with NMR relaxation-rate, specific-heat and thermal-conductivity measurements. In addition, both have total spin component $S_z$=0, compatible with the observation of a pronounced Knight shift and $H_{c2}$ Pauli limiting. For parameter values appropriate to UPd${}_2$Al${}_3$, we determine the dependence of the superconducting transition temperature $T_c$ on a phenomenological coupling constant $g$ and we investigate the associated mass enhancement and its anisotropy.

arXiv comment11 pages, 2 figures, 1 table

References in corpus (8)

• Heavy-fermion superconductivity in CeCoIn5 at 2.3K
• Low temperature specific heat of the heavy fermion superconductor PrOs${}_4$Sb${}_{12}$
• Fermi surface and heavy masses for UPd${}_2$Al${}_3$
• First order superconducting transition near a ferromagnetic quantum critical point
• The Nature of Heavy Quasiparticles in Magnetically Ordered Heavy Fermions
• Low Frequency Spin Dynamics in the CeMIn_5 Materials
• Dual model for magnetic excitations and superconductivity in UPd2Al3
• Gap Symmetry an Thermal Conductivity in Nodal Superconductors

Cited by in corpus (11)

• Superconducting phases of f-electron compounds
• Unconventional Superconductivity
• Superconductivity in Uranium Ferromagnets
• Theory of magnetic excitons in the heavy-fermion superconductor $UP{d}_{2}A{l}_3$
• Magnetic relaxation in uranium ferromagnetic superconductors
• Superconductivity in heavy fermion compounds
• Field-angle resolved specific heat and thermal conductivity in the vortex phase of UPd_2Al_3
• Thermal conductivity in the vortex state of the superconductor UPd_2Al_3
• Theory of tunneling spectroscopy in UPd2Al3
• Triplet superconductivity in ferromagnets due to magnon exchange
• Theory of dual fermion superconductivity in hole-doped cuprates