Anomalous magnetophotoluminescence as a result of level repulsion in arrays of quantum dots
E.V. Tsiper, P.D. Wang, J.L. Merz, A.L. Efros, S. Fafard, D. Leonard, and P.M. Petroff
Department of Physics, University of Utah, Salt Lake City, UT 84112
Selectively excited photoluminescence (SPL) of an array of
self-organized In0.5Ga0.5As quantum dots has
been measured in a magnetic field up to 11T. An anomalous magnetic
field sensitivity of the SPL spectra has been observed under
conditions for which the regular photoluminescence spectra are almost
insensitive to the magnetic field due to large inhomogeneous
broadening. The anomalous sensitivity is interpreted in terms of the
repulsion of excited levels of the dots in a random potential. A
theory presented to describe this phenomenon is in excellent agreement
with the experimental data. The data estimated the correlation in the
positions of excited levels of the dots to be 94%. The magnetic field
dependence allows the determination of the reduced cyclotron effective
mass in a dot. For,our sample we have obtained
memh/(me+mh)=0.034mo.