| Автор | M J Smith |
| Автор | P N Butcher |
| Дата выпуска | 1989-02-20 |
| dc.description | Phonon drag thermopower S<sub>g</sub> calculations are presented for a quasi-2D electron gas at the (100) plane in a Si MOSFET and compared with previous theory and experiment. Without screening -S<sub>g</sub> is improved to a factor of approximately 16 times larger than experiment (from approximately 35). Multi-sub-band screening is considered and its importance assessed in the experimental range (2-6 K and electron densities to 10<sup>16</sup> m<sup>-2</sup>) but a single sub-band approximation is found to be sufficient and gives thermopowers just approximately 40% different from experiment. Further improvement is made by adopting the Fang and Howard variational wavefunction and better material parameters. The best agreement is found to be about 5% at temperatures in the mid-range (4 K) and for the highest electron densities. The same excellent qualitative agreement with experiment is retained including the peak in -S<sub>g</sub>/T<sup>3</sup> whose presence is explained by enhanced phonon absorption around the Kohn resonance (q approximately=2k<sub>F</sub>). The peak positions move up in temperature (by about 0.75 K) because the dominant q-value increases and reduces the effect of screening on S<sub>g</sub> at higher T. In GaAs/GaAlAs heterojunctions S<sub>g</sub> is much less sensitive to screening effects because the screening constant is much smaller in GaAs than it is in Si. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | A calculation of the effect of screening on phonon drag thermopower in a Si MOSFET |
| Тип | paper |
| DOI | 10.1088/0953-8984/1/7/010 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 1 |
| Первая страница | 1261 |
| Последняя страница | 1273 |
| Аффилиация | M J Smith; Dept. of Phys., Warwick Univ., Coventry, UK |
| Аффилиация | P N Butcher; Dept. of Phys., Warwick Univ., Coventry, UK |
| Выпуск | 7 |
