Beaulac Rémi, Schneider Lars, Archer Paul I, Bacher Gerd, Gamelin Daniel R
Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA.
Science. 2009 Aug 21;325(5943):973-6. doi: 10.1126/science.1174419.
An attractive approach to controlling spin effects in semiconductor nanostructures for applications in electronics is the use of light to generate, manipulate, or read out spins. Here, we demonstrate spontaneous photoinduced polarization of manganese(II) spins in doped colloidal cadmium selenide quantum dots. Photoexcitation generates large dopant-carrier exchange fields, enhanced by strong spatial confinement, that lead to giant Zeeman splittings of the semiconductor band structure in the absence of applied magnetic fields. These internal exchange fields allow spontaneous magnetic saturation of the manganese(II) spins to be achieved at zero external magnetic field up to approximately 50 kelvin. Photomagnetic effects are observed all the way up to room temperature.
在电子学应用中，一种用于控制半导体纳米结构中自旋效应的有效方法是利用光来产生、操纵或读出自旋。在此，我们展示了掺杂的胶体硒化镉量子点中锰（II）自旋的自发光致极化。光激发产生了大的掺杂剂 - 载流子交换场，这种场因强空间限制而增强，在没有外加磁场的情况下导致半导体能带结构的巨大塞曼分裂。这些内部交换场使得在零外磁场下，高达约50开尔文时能够实现锰（II）自旋的自发磁饱和。一直到室温都能观察到光磁效应。
