Gap modification of atomically thin boron nitride by phonon mediated   interactions
  A theory is presented for the modification of bandgaps in atomically thin boron nitride (BN) by attractive interactions mediated through phonons in a polarizable substrate, or in the BN plane. Gap equations are solved, and gap enhancements are found to range up to 70% for dimensionless electron-phonon coupling \lambda=1, indicating that a proportion of the measured BN bandgap may have a phonon origin. 
J. P. Hague
cond-mat.mes-hall cond-mat.str-el