Magnetoresistance in a two-dimensional impurity band
The effect of a magnetic field perpendicular to the surface on the conductance of the two-dimensional (2D) Na+ induced impurity band in silicon inversion layers has been studied. The temperature dependence of the conductance at low fields (H < 5T) σ = σo′exp-(To′/T)1/13, which is expected for variable range hopping in 2-D when the impurity wave functions are hydrogenic. At higher fields (H > 10T), σ = σoexp-(To/T)1/12, which should result for Landau (Gaussian) impurity wave functions. In this high field regime we observe To = aH, where a depends only on the density of states at the Fermi level and fundamental constants. The density of states derived in this way is about an order of magnitude larger than the density of states inferred from earlier measurements and is even approaching the magnitude of the free electron density of states.
KeywordsMagnetic Field High Magnetic Field Magnetic Field Dependence Impurity Band Negative Magnetoresistance
Unable to display preview. Download preview PDF.
- 2.A. Hartstein and A. B. Fowler, Proc. of 13th Int. Conf. on Phys. of Semicond., Rome, p.741 (1976).Google Scholar
- 3.A. Hartstein and A. B. Fowler, Proc. of 14th Int. Conf. on Phys. of Semicond., Edinburgh, p.1001 (1978).Google Scholar
- 4.A. B. Fowler and A. Hartstein, Phil. Mag. B 42, 949 (1980).Google Scholar
- 5.See for example, J. A. Chroboczek, Phil. Mag. B 42, 933 (1980).Google Scholar
- 6.A. Hartstein and A. B. Fowler, J. Phys. C 8, L249 (1975).Google Scholar
- 8.Y. Ono, J. Phys. Soc. Japan 51, 237 (1982).Google Scholar
- 9.K. J. Hayden and P. N. Butcher, Phil. Mag. B 38, 603 (1979).Google Scholar
- 10.B. Movaghar and L. Schweitzer, J. Phys. C11, 125 (1978).Google Scholar
- 11.H. Kamimura, A. Kurobe and T. Takemori, to be published in the Proc. of the 16th Int. Conf. on the Phys. of Semiconductors, 1982.Google Scholar