Institute of Solid State Physics, RAS, Chernogolovka, 142432 Russia.
Phys Rev Lett. 2010 Dec 17;105(25):256401. doi: 10.1103/PhysRevLett.105.256401. Epub 2010 Dec 14.
The effect of a magnetic field on a spinor exciton-polariton condensate has been investigated. A quenching of a polariton Zeeman splitting and an elliptical polarization of the condensate have been observed at low magnetic fields B<2 T. The effects are attributed to a competition between the magnetic field induced circular polarization buildup and the spin-anisotropic polariton-polariton interaction which favors a linear polarization. The sign of the circular polarization of the condensate emission at B<3 T is negative, suggesting that a dynamic condensation in the excited spin state rather than the ground spin state takes place in this magnetic field range. From about 2T on, the Zeeman splitting opens and from then on the slope of the circular polarization degree changes its sign. For magnetic fields larger than the 3 T, the upper spin state occupation is energetically suppressed and circularly polarized condensation takes place in the ground state.
磁场对自旋激子极化激元凝聚体的影响已经被研究过了。在低磁场 B<2 T 下，观察到极化激元塞曼分裂的猝灭和凝聚体的椭圆偏振。这些效应归因于磁场诱导的圆偏振积累和自旋各向异性极化激元-极化激元相互作用之间的竞争，后者有利于线偏振。在 B<3 T 下，凝聚体发射的圆偏振的符号为负，这表明在这个磁场范围内发生的是激发态而不是基态的动态凝聚。从大约 2 T 开始，塞曼分裂打开，从那时起，圆偏振度的斜率改变了符号。对于大于 3 T 的磁场，上自旋态占据被能量抑制，并且在基态中发生圆偏振凝聚。
