Frustrated Heavy Fermion Metals

Schematic structure of the model studied. Each site hosts interacting localized spin and a conduction electron
Phase diagram: The VBS-AFM transition field is suppressed and superconductivity appears; in the AFM phase spin-density wave like gaps open near field determined by filling (shaded green areas.

PNAS 117 (34) 20462 (2020)

An interplay between Kondo screening and magnetic frustration may lead to novel phases of matter and exotic excitations. Also, a number of corresponding heavy fermion materials exist, such as YbAl3C3 and CeAgBi2.

As an example I have studied a 1D spin ladder model with a nonmagnetic valence bond solid (VBS) ground state in the presence of conduction electrons and magnetic field. I have shown that the critical field for the transition is suppressed by Kondo coupling, and novel phenomena, such as SDW gap phase (shown in green) or sign-changing superconductivity may occur. Results of the analytical predictions have been shown to be in excellent agreement with DMRG calculations.

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