1207.3701 (K. Ziegler)

Dynamic symmetry breaking in a 2D electron gas with a spectral node    [PDF]

K. Ziegler

We study a 2D electron gas with a spectral node and a random gap in a vicinity of the node. After identifying the fundamental dynamic symmetries of this system, the spontaneous breaking of the latter by a Grassmann field is studied within a nonlinear sigma model approach. This allows us to reduce the average two-particle Green's function to a diffusion propagator with a random diffusion coefficient. The latter has non-degenerate saddle points and is treated by the conventional self-consistent Born approximation. This leads to a renormalized chemical potential and diffusion coefficient, where the DC conductivity increases linearly with the density of quasiparticles.

View original: http://arxiv.org/abs/1207.3701