Theory of a nematic phase of a heavy fermion compound: symmetry breaking in the hybridization channel

Electronic nematicity, the spontaneous breaking of rotational symmetry of an electronic fluid, has been found in various systems, from unconventional superconductors to moire systems. Recent STM/STS experiments have shown a similar C₄-symmetry breaking in USbTe, a moderately heavy fermion compound. In this work, we show that a mechanism for the latter can be achieved by considering an infinite-U Anderson lattice with a tetragonal symmetry preserving hybridization term between localized f_xyz and itinerant p_z electrons. A Falikov-Kimball term, a Coulomb interaction term between f and p electrons (U_fp), then drives a nematic transition in the singlet f-p hybridization channel within the heavy Fermi liquid phase. A signature of this transition can be seen by computing the differential conductance probed in STM/STS measurements. Our work provides a novel mechanism for nematicity in the hybridization channel of heavy fermion compounds that emerges inside the heavy Fermi liquid phase.