Collapse of High Field Magnetophonon Resonance in GaAs-GaAlAs Heterojunctions

D.R. Leadley¹, R.J. Nicholas¹, J. Singleton^1,4, W. Xu^2,3, F.M. Peeters², J.T. Devreese², J.A.A.J. Perenboom⁴, L. van Bockstal⁵, F. Herlach⁵, J.J. Harris⁶ and C.T. Foxon⁷

1. Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
2. Departement Natuurkunde, Universiteit Antwerpen (UIA), Universiteitsplein 1, B-2610 Antwerpen, Belgium
3. Department of Theortical Physics, The Australian National University, Canberra, ACT 0200, Australia.
4. Univerisity of Nijmegen, Toerooiveld 1, NL-6525 ED, Nijmegen, The Netherlands
5. Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001, Leuven, Belgium.
6. Department of Electronics and Electrical Engineering, University College London, WC1E 6BT, UK
7. Department of Physics, University Park, Nottingham, NG7 2RD, UK

Magnetophonon resonance is studied in the resistivity of high mobility GaAs-GaAlAs heterojunctions. In contrast to previous studies which showed an exponentially damped series of oscillations, we find this only at low magnetic fields. At high fields the oscillation amplitude decreases, leading to collapse of the fundamental resonance. Fully self-consistent calculations, including all scattering processes, show the Landau level width oscillates in field and explain the unusual behavior.

Physical Review Letters, 73, 589 (1994)