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HL: Halbleiterphysik

HL 7: Poster I

HL 7.40: Poster

Monday, March 26, 2001, 10:30–19:00, Rang S\ 3

Temperature Dependence of the mean carrier Lifetime in Graphite determined by Hall conductivity — •Heiko Kempa, Falk Mrowka, and Pablo Esquinazi — Abt. Supraleitung und Magnetismus, Institut für Experimentelle Physik II, Universität Leipzig, D-04103 Leipzig

We have performed simultaneous measurements of the longitudinal and transverse (Hall) electrical resistivity as a function of magnetic field applied normal to the planes of highly oriented pyrolytic graphite samples at different temperatures (0.1 K ≤ T ≤ 200 K). Inverting the resistivity matrix in two dimensions we obtained the Hall conductivity as a function of applied field. The Hall conductivity follows approximately the simple free-electron field dependence. From this dependence we obtained that the ratio between the mean carrier scattering time and effective mass is inversely proportional to the temperature τ/m^∗≃ (3.5 ± 1) 10²¹ (1/T) K s kg⁻¹ for T ≥ 20 K. This dependence as well as the absolute value agree with the results obtained from photoemission spectroscopy for energies larger than 0.2 eV [1] and interpreted in terms of electron-plasmon or electron-electron [2] interaction. In the literatur, however, the low temperature mobility we measured is supposed to be due to electron-phonon scattering.

[1] S. Xu et al., Phys. Rev. Lett. 76, 483 (1996).

[2] J. Gonzalez et al. Phys. Rev. Lett. 77, 3589 (1996).