Large phonon-drag enhancement induced by narrow quantum confinement at   the LaAlO3/SrTiO3 interface
  The thermoelectric power of the two-dimensional electron system (2DES) at the LaAlO3/SrTiO3 interface is explored below room temperature, in comparison with that of Nb-doped SrTiO3 single crystals. For the interface we find a region below T =50 K where thermopower is dominated by phonon-drag, whose amplitude is hugely amplified with respect to the corresponding bulk value, reaching values ~mV/K and above. The phonon-drag enhancement at the interface is traced back to the tight carrier confinement of the 2DES, and represents a sharp signature of strong electron-acoustic phonon coupling at the interface. 
I. Pallecchi, F. Telesio, D. Marre', D. Li, S. Gariglio, J.-M.   Triscone, A. Filippetti
cond-mat.str-el cond-mat.mes-hall