Düsseldorf 2007 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 22: Poster
P 22.38: Poster
Donnerstag, 22. März 2007, 16:30–18:30, Poster A
Crystallization in mass-asymmetric electron-hole bilayers — Patrick Ludwig1,2, Alexei Filinov1,3, Yurii Lozovik3, Heinrich Stolz2, and •Michael Bonitz1 — 1CAU zu Kiel, ITAP, Leibnizstraße 15, D-24098 Kiel — 2Universität Rostock, Institut für Physik, Universitätsplatz 3, D-18051 Rostock — 3Institute of Spectroscopy RAS, Moscow region, Troitsk, 142190, Russia
We focus on the effect of the mass ratio on crystal formation in quantum electron-hole bilayers. Varying the mass ratio M of holes and electrons between 1 and 100 for a fixed layer separation at low temperature and high density, one can tune the hole behavior from delocalized (quantum) to localized (quasi-classical) while the electrons remain delocalized all the time.
As was recently observed for bulk semiconductors [1], holes undergo a phase transition to a crystalline state if the mass ratio exceeds a critical value of Mcr ≈ 80. Here, we extend this analysis to bilayers where Mcr can be drastically reduced by properly choosing d and the in-layer particle density. The complicated overlap of correlation and quantum effects of both, electrons and holes, is fully taken care of by performing first-principle path integral Monte Carlo simulations. We present results for two types of e-h bilayers: a mesoscopic system of N = 36 particles in a parabolic trap and for a macroscopic system of the same density.
[1] M. Bonitz, V.S. Filinov, V.E. Fortov. P.R. Levashov, and H. Fehske, Phys. Rev. Lett. 95, 235006 (2005)