Partial Kondo screening and anomalous thermal conductance

Abstract

The frustrated magnetism on the Kondo lattice system motivates intriguing Kondo breakdown beyond the traditional Doniach scenario. Among them, the fractionalized Fermi liquid (FL*) has drawn particular interest by virtue of its fractionalized nature. Here we study the phase diagram of the J(1)-J(2) Kondo-Heisenberg model on a honeycomb lattice at a quarter filling. Employing the slave-fermion mean-field theory with d +/- id spin liquid ansatz and exact diagonalization, we discuss the emergence of partial Kondo screening in the frustrated regime with comparable J(1) and J(2), and the fractionalized superconductor (SC*), which is a superconductor analogy of the FL*. Due to the larger number of local spin moments than itinerant electrons, the magnetic fluctuation is still significant even in the strong-coupling limit, which influences the thermodynamic and transport properties qualitatively. In particular, we estimate the thermal conductance to probe the low-energy excitation and show the anomalous behavior in the SC* phase in contrast to the conventional superconductors.