Spin Physics of Excitons in Colloidal Nanocrystals

• Published in: Physics of the solid state Vol. 60; no. 8; pp. 1537 - 1553
• Main Authors: Rodina, A. V., Golovatenko, A. A., Shornikova, E. V., Yakovlev, D. R.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.08.2018; Springer; Springer Nature B.V
• Subjects: Admixtures; Circular polarization; Colloids; Comparative analysis; COMPARATIVE EVALUATIONS; DETECTION; Electron spin; EXCITONS; Ferromagnetism; MAGNETIC FIELDS; Nanocrystals; NANOSCIENCE AND NANOTECHNOLOGY; NANOSTRUCTURES; PHOTOLUMINESCENCE; Physics; Physics and Astronomy; POLARIZATION; POLARONS; Radiative recombination; RECOMBINATION; SEMICONDUCTOR MATERIALS; Semiconductors; Semiconductors (Materials); Solid State Physics; SPIN; SURFACES; Trions
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S106378341808019X

We present a review of spin-dependent properties of excitons in semiconductor colloidal nanocrystals. The photoluminescences (PL) properties of neutral and charged excitons (trions) are compared. The mechanisms and the polarization of radiative recombination of a “dark” (spin-forbidden) exciton that determines the low-temperature PL of colloidal nanocrystals are discussed in detail. The radiative recombination of a dark exciton becomes possible as a result of simultaneous flips of the surface spin and electron spin in a dark exciton that leads to admixture of bright exciton states. This recombination mechanism is effective in the case of a disordered state of the spin system and is suppressed if the polaron ferromagnetic state forms. The conditions and various mechanisms of formation of the spin polaron state and possibilities of its experimental detection are discussed. The experimental and theoretical studies of magnetic field-induced circular polarization of PL in ensembles of colloidal nanocrystals are reviewed.