2008/10/01 by O. Krebs, B. Eblé, B. Eble +7 · 1 citation
Engineering · Physics and Astronomy · #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #Semiconductor materials and devices #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.crhy.2008.10.001
published as C. R. Physique 9, 874 (2008) · 10 pages, 5 figures
openalex publication_date 2008/10/01 · arxiv created 2009/04/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report on the influence of the hyperfine interaction on the optical orientation of singly charged excitons <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi>X</mml:mi> <mml:mo>±</mml:mo> </mml:msup> </mml:math> in self-assembled InAs/GaAs quantum dots. All measurements were carried out on individual quantum dots studied by micro-photoluminescence at low temperature. We show that the hyperfine interaction leads to an effective partial spin relaxation, under 50 kHz modulated excitation polarization, which becomes, however, strongly inhibited under steady optical pumping conditions because of dynamical nuclear polarization. This optically created magnetic-like nuclear field can become very strong (up to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mn>4</mml:mn> <mml:mtext>T</mml:mtext> </mml:math> ) when it is generated in the direction opposite to a longitudinally applied field, and exhibits then a bistability regime. This effect is very well described by a theoretical model derived in a perturbative approach, which reveals the key role played by the energy cost of an electron spin flip in the total magnetic field. Finally, we emphasize the similarities and differences between <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi>X</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi>X</mml:mi> <mml:mo>−</mml:mo> </mml:msup> </mml:math> trions with respect to the hyperfine interaction, which turn out to be in perfect agreement with the theoretical description.