Coherent spin precession of electrons and excitons in charge tunable InP quantum dots

✍ Scribed by Yasuaki Masumoto; Keisuke Kawana; Shinichi Tomimoto

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 240 KB
• Volume: 42
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/j.physe.2009.10.014

✦ Synopsis

Coherent spin precession of electrons and excitons is observed in charge tunable InP quantum dots under the transverse magnetic field by means of time-resolved Kerr rotation. In a quantum dot doped by one electron, spin precession of the doped electron in the quantum dot starts out of phase with spin precession of the doped electrons in a GaAs substrate just after a trion is formed and persists for more than 2 ns even after the trion recombines. Simultaneously spin precession of a trion (hole) starts. Observation of spin precession of both a doped electron and a trion (hole) confirms creating coherent superposition of an electron and a trion as the initialization process of spin of doped electrons in quantum dots. In a neutral quantum dot, the exciton spin precession starts out of phase with spin precession of the doped electrons in a GaAs substrate and the precession frequency does not converge to 0 at the zero field limit. It contains the electron-hole exchange interaction and corresponds to the splitting between bright and dark excitons under the transverse magnetic field.