Interaction effects in graphene in a weak magnetic field

A weak perpendicular magnetic field, B, breaks the chiral symmetry of each valley in the electron spectrum of graphene, preserving the overall chiral symmetry in the Brillouin zone. We explore the consequences of this symmetry breaking for the interaction effects in graphene. In particular, we demonstrate that the electron-electron interaction lifetime acquires an anomalous B dependence. Also, the ballistic zero-bias anomaly, delta nu(omega), where omega is the energy measured from the Fermi level, emerges at a weak B and has the form delta nu(B) similar to B-2/omega(2). Temperature dependence of the magnetic-field corrections to the thermodynamic characteristics of graphene is also anomalous. We discuss experimental manifestations of the effects predicted. The microscopic origin of the B-field sensitivity is an extra phase acquired by the electron wave function resulting from the chirality-induced pseudospin precession.

Automated summary

The presence of a weak perpendicular magnetic field in graphene breaks the chiral symmetry of each valley in the electron spectrum, leading to anomalous dependencies in the electron-electron interaction lifetime and magnetic field corrections to the thermodynamic characteristics. Experiments are discussed to explore the effects predicted by this symmetry breaking.