We revisit 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 semiclassical 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. One of the main effects of the nematoelastic coupling is to smooth the electronic nonequilibrium distribution function, making it approach the simple cosine angular dependence even when the impurity scattering is not too strong. We find that at temperatures lower than a temperature scale set by the nematoelastic coupling, the resistivity shows the T2 behavior characteristic of a Fermi liquid. This is in contrast to the T4/3 lowerature behavior expected for a lattice-free nematic quantum critical point. More importantly, we show that the effective resistivity exponent αeff(T) in ρ(T)-ρ0∼Tαeff(T) 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.
Bibliographical noteFunding Information:
We would like to thank A. Chubukov, A. Coldea, A. Klein, E. Miranda, H. Freire, I. Paul, and A. Schofield for stimulating discussions. V.S.d.C. is grateful for the financial support from FAPESP under Grant No. 2017/16911-3. R.M.F. is supported by the US Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-SC0012336.
© 2019 American Physical Society.