3 research outputs found
Solvable Theory of a Strange Metal at the Breakdown of a Heavy Fermi Liquid
We introduce an effective theory for quantum critical points in heavy fermion
systems involving a change in carrier density without symmetry breaking. The
new theory captures a strong coupling metallic fixed point, leading to robust
marginal Fermi liquid transport phenomenology, within a controlled large
limit. This is contrasted with the conventional so-called "slave boson" theory
of the Kondo breakdown, where the large limit describes a weak coupling
fixed point and non-trivial transport behavior may only be obtained through
uncontrolled corrections. We compute the weak field Hall coefficient
within the effective model as the system is tuned across the transition. We
find that between the two plateaus, reflecting the different carrier densities
in the two Fermi liquid phases, the Hall coefficient can develop a peak in the
critical crossover regime, consistent with recent experimental findings. In the
regime of strong damping of emergent bosonic excitations, the critical point
also displays a near-universal "Planckian" transport lifetime,
.Comment: 20 pages, 10 figures, Supplement include