†Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia.
‡Naval Research Laboratory, Washington, DC 20375, United States.
Nano Lett. 2015 Jun 10;15(6):4214-22. doi: 10.1021/acs.nanolett.5b01566. Epub 2015 May 5.
We predict theoretically that nonmagnetic CdSe nanocrystals may possess macroscopic magnetic moments due to the formation of dangling-bond magnetic polarons (DBMPs). A DBMP is created in optically pumped nanocrystals by dynamic polarization of dangling bond spins (DBSs) at the nanocrystal surface during radiative recombination of the ground state "dark" exciton assisted by a spin-flip of the DBS. The formation of DBMPs suppresses the radiative recombination of the dark exciton and leads to a temperature-dependent contribution to the Stokes shift of the photoluminescence. This model consistently explains the experimentally observed low-temperature photoluminescence features of nonmagnetic CdSe nanocrystals as manifestations of their spin-related magnetic properties.
我们从理论上预测，由于悬键磁极化子（DBMP）的形成，非磁性 CdSe 纳米晶体可能具有宏观磁矩。在通过基态“暗激子”辐射复合辅助的 DBS 自旋翻转来动态极化纳米晶表面的悬键自旋（DBS）而在光学泵浦纳米晶体中产生 DBMP。DBMP 的形成抑制了暗激子的辐射复合，并导致光致发光斯托克斯位移的温度依赖性贡献。该模型一致地解释了实验观察到的非磁性 CdSe 纳米晶体在低温下的光致发光特征，这是其与自旋相关的磁性性质的表现。
