Título:  “Fingerprints of acoustic phonons on the electrical resistivity at the onset of nematic quantum criticality”

Resumo:

In this talk, we address the issue of the resistivity of a two-dimensional electronic system tuned to a nematic quantum critical point (QCP), focusing on the nontrivial impact of the coupling to the acoustic phonons. Due to the unavoidable linear coupling between the electronic nematic order parameter and the lattice strain fields, long-range nematic interactions mediated by the phonons emerge in the problem. By solving the semi-classical Boltzmann equation in the presence of scattering by impurities and nematic fluctuations, we determine the temperature dependence of the resistivity as the nematic QCP is approached. We find that at temperatures lower than a temperature scale set by the nemato-elastic coupling, the resistivity shows the T2 behavior characteristic of a Fermi liquid. This is in contrast to the T4/3 low-temperature behavior expected for a lattice-free nematic quantum critical point. More importantly, we show that the effective resistivity exponent displays a pronounced temperature dependence, implying that a nematic QCP cannot generally be characterized by a simple resistivity exponent. We discuss the implications of our results to the interpretation of experimental data, particularly in the nematic superconductor FeSe1-xSx.