Lattice thermal conductivity of a quantum well limited by umklapp, impurity, and boundary scattering was investigated theoretically by taking into account dispersion of confined acoustic-phonon modes. We show that strong modification of phonon group velocities due to spatial confinement leads to a significant increase in the phonon relaxation rates. From the numerical calculations, we predict a decrease by an order of magnitude of the lattice thermal conductivity in a 100-Å-wide free-standing quantum well. Our theoretical results are consistent with recent experimental investigations of the lateral thermal conductivity of nitride/silicon/oxide membranes conducted in our group.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1998|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics