Pseudospin in optical and transport properties of graphene
  We show that the pseudospin being an additional degree of freedom for carriers in graphene can be efficiently controlled by means of the electron-electron interactions which, in turn, can be manipulated by changing the substrate. In particular, an out-of-plane pseudospin component can occur leading to a zero-field Hall current as well as to polarization-sensitive interband optical absorption. 
Maxim Trushin and John Schliemann
cond-mat.mes-hall cond-mat.mtrl-sci