Spatially Indirect Excitons in GaAs/Al0.35Ga0.65As Double Quantum Wells in the Presence of In-Plane Magnetic Fields

✍ Scribed by Parlangeli, A. ;Christianen, P.C.M. ;Maan, J.C. ;Soerensen, C.B. ;Lindelof, P.E.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 183 KB
• Volume: 178
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/1521-396x(200003)178:1<45::aid-pssa45>3.0.co;2-4

✦ Synopsis

We studied the optical properties of GaAs/Al 0X35 Ga 0X65 As asymmetric double quantum wells at T 4X2 K and in the presence of in-plane magnetic fields up to 20 T. In an electric field F 8 45 kV/cm, electrons and holes are respectively confined in the wide and narrow well and form spatially indirect excitons with a binding energy of $3X5 meV. The photoluminescence (PL) peak shifts diamagnetically by 0.02 meV/T 2 and is quenched by fields of $5 T, the suppression being stronger at higher biases. The experimental results are well explained by numerical calculations which show that the magnetic field makes the e±h recombination indirect also in k-space. The suppression of the PL cannot be described in the picture of free e±h pairs, but rather scales as the ratio between the magnetic length and the e±h distance; we therefore believe that it is a peculiar manifestation of the exciton binding.