Abstract
High magnetic fields induce a pronounced in-plane electronic anisotropy in the tetragonal antiferromagnetic metal at for fields off the axis. Here we investigate the response of the underlying crystal lattice in magnetic fields to 45 T via high-resolution dilatometry. At low fields, a finite magnetic field component in the tetragonal plane explicitly breaks the tetragonal () symmetry of the lattice revealing a finite nematic susceptibility. A modest -axis expansion at hence marks the crossover to a fluctuating nematic phase with large nematic susceptibility. Magnetostriction quantum oscillations confirm a Fermi surface change at with the emergence of new orbits. By analyzing the field-induced change in the crystal-field ground state, we conclude that the in-plane Ce hybridization is enhanced at , in agreement with the in-plane lattice expansion. We argue that the nematic behavior observed in this prototypical heavy-fermion material is of electronic origin, and is driven by the hybridization between and conduction electrons which carries the -electron anisotropy to the Fermi surface.
- Received 14 March 2018
- Revised 26 September 2018
DOI:https://doi.org/10.1103/PhysRevLett.122.016402
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