Prus O, Reznikov M, Sivan U, Pudalov V
Department of Physics and Solid State Institute, Technion-IIT, Haifa 32000, Israel.
Phys Rev Lett. 2002 Jan 7;88(1):016801. doi: 10.1103/PhysRevLett.88.016801. Epub 2001 Dec 14.
Low temperature cooling of two-dimensional electrons in silicon-metal-oxide semiconductor field effect transistors is studied experimentally and found to be more effective than expected from the bulk electron-phonon coupling in silicon. The extracted heat transfer rate to phonons depends cubically on electron temperature, suggesting that piezoelectric coupling, which is absent in bulk silicon, dominates over deformation potential. As a result, at 100 mK, electrons farther than approximately 100 microm from the contacts are mostly cooled by phonons. Using long devices and low excitation voltage we measure electron resistivity down to approximately 100 mK and find that some of the "metallic" curves turn insulating below approximately 300 mK.
