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Cerium-based ternary compounds CeNi 2 Cd 20 and CePd 2 Cd 20 do not exhibit long-range order down to millikelvin temperature range. Given the large separation between Ce ions which significantly reduces the super-exchange interactions and vanishingly small Ruderman-Kittel-Kasuya-Yosida interaction, here we show that nodal superconductivity mediated by the valence fluctuations must be a ground state in these materials. We propose that the critical temperature for the superconducting transition can be significantly increased by applying hydrostatic pressure. We employ an extended periodic Anderson lattice model which includes the long-range Coulomb interactions between the itinerant electrons as well as the local Coulomb interaction between the predominantly localized and itinerant electrons to compute a critical temperature of the superconducting transition. Using the slave-boson approach we show that fluctuations mediated by the repulsive electron-electron interactions lead to the emergence of d -wave superconductivity., (Creative Commons Attribution license.)

We have theoretically analysed DC resistivity ( ρ ) in the Kondo-lattice materials using the powerful memory function formalism. The complete temperature evolution of ρ is investigated using the Wölfle-Götze expansion of the memory function. The resistivity in this model originates from spin-flip magnetic scattering of conduction s -electron off the quasi-localized d or f electron spins. We find the famous resistivity upturn in lower temperature regime ( k B T ≪ μ d ), where μ d is the effective chemical potential of d -electrons. In the high temperature regime ( μ d ≪ k B T ) we discover that resistivity scales as cube root of T (ρ∝T32). Our results are in reasonable agreement with the experimental results reported in the literature., (© 2020 IOP Publishing Ltd.)