arXiv:1210.3043 · Physical Review B
Pomeranchuk-nematic instability in the presence of a weak magnetic field
Daniel Gustavo Barci, Daniel Reyes
Abstract
We analyze a two-dimensional Pomeranchuk-nematic instability, trigger by the Landau parameter ${F}_{2}<0$, in the presence of a small magnetic field. Using Landau Fermi-liquid theory in the isotropic phase, we analyze the collective modes near the quantum critical point ${F}_{2}=\ensuremath{-}1,{\ensuremath{\omega}}_{c}=0$ (where ${\ensuremath{\omega}}_{c}$ is the cyclotron frequency). We focus on the effects of parity symmetry breaking on the Fermi-surface deformation. We show that the linear response approximation of the Landau-Silin equation is not sufficient to study the critical regime and it is necessary to compute corrections at least of order ${\ensuremath{\omega}}_{c}^{2}$. Identifying the slowest oscillation mode in the disordered phase, we compute the phase diagram for the isotropic/nematic phase transition in terms of ${F}_{2}$ and ${\ensuremath{\omega}}_{c}$.