Theory of the effect of a DC magnetic field on surface space-charge-wave/optical phonon instabilities in semiconductor media

• Published in: Surface science Vol. 310; no. 1; pp. 399 - 406
• Main Authors: Martin, E.G., Wallis, R.F.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.05.1994; Amsterdam Elsevier Science; New York, NY
• Subjects: Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Collective excitations (including plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Surface and interface electron states; Surface states, band structure, electron density of states; Optical phonons; Semiconductor materials; Surface waves; Dispersion relations; Space charge; Magnetic field effects; Theoretical study; Polaritons
• DOI: 10.1016/0039-6028(94)91402-8
• ISSN: 0039-6028

A theoretical investigation has been carried out on the effect of a DC magnetic field on surface space-charge-wave instabilities caused by a drift current parallel to the surface of a doped polar semiconductor. The magnetic field is taken as perpendicular to the semiconductor surface. The dispersion relation is obtained using a generalization of the Kliewer-Fuchs specular-reflection boundary conditions. Calculated results are obtained in the non-retarded limit for two cases: (1) where a current-carrying, nonpolar semiconductor interfaces a polar insulator half-space and (2) where a current-carrying, polar semiconductor interfaces a nonpolar insulator half-space. Convective or amplifying instabilities arise because of the presence of optical phonons. Numerical results are presented for the gain as a function of frequency and magnetic field.