Zero-Field Satellites of a Zero-Bias Anomaly

Spin-orbit (SO) splitting, $\pm \omega_{SO}$, of the electron Fermi surface in two-dimensional systems manifests itself in the interaction-induced corrections to the tunneling density of states, $\nu (\epsilon)$. Namely, in the case of a smooth disorder, it gives rise to the satellites of a zero-bias anomaly at energies $\epsilon=\pm 2\omega_{SO}$. Zeeman splitting, $\pm \omega_{Z}$, in a weak parallel magnetic field causes a narrow {\em plateau} of a width $\delta\epsilon=2\omega_{Z}$ at the top of each sharp satellite peak. As $\omega_{Z}$ exceeds $\omega_{SO}$, the SO satellites cross over to the conventional narrow maxima at $\epsilon = \pm 2\omega_{Z}$ with SO-induced plateaus $\delta\epsilon=2\omega_{SO}$ at the tops.