Theory of magneto-excitons in quantum wells

Theory of magneto-excitons in quantum wells

Surface Science 196 (1988) 533 North-Holland, Amsterdam 533 EXTENDED ABSTRACT THEORY OF MAGNETO-EXCITONS IN QUANTUM WELLS S.-R. ERIC YANG Department...

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Surface Science 196 (1988) 533 North-Holland, Amsterdam

533

EXTENDED ABSTRACT THEORY OF MAGNETO-EXCITONS IN QUANTUM WELLS S.-R. ERIC YANG Department of Physics, University of Maryland, College Park, MD 20 742, USA

and L.J. SHAM Department of Physics, B-OI 9, University of California at San Diego, La J6lla, CA 92093, USA Received 1 June 1987; accepted for publication 1 June 1987

With the advent of several very precise magneto-optical studies in undoped quantum wells, the hydrogenic exciton model is proving to be an inadequate framework for interpreting the data. A theory [ 1] of excitons in a high magnetic field normal to the confining quantum well of III-V semiconductors taking into account the effect of the bulk valence band complex is presented. Three central points follow from the theory. (1) It is sometimes thought that the magneto-optical spectrum should consist of lines corresponding to unbound electron-hole pair Landau levels as well as bound excitons. The discrete bound e×citon lines, which deviate in energy from the free electron-hole pairs, are the only observable spectral lines [ 2 ]. (2) The field dependence of all lines is non-linear. (3) The strong mixing of the heavy and light hole subbands gives rise to extra exciton lines not present in the hydrogenic model. These salient features lead to a drastic re-interpretation of the magneto-optical spectra in comparison with the calculated excitonic spectra.

References [ 1 ] S.-R. Eric Yang and L.J. Sham, Phys. Rev, Letters 58 (I 987) 2598. [ 2 ] O. Akimoto and H. Hasagawa, J. Phys. Soc. Japan 22 ~1967 ~ ~8 I.

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