Boehme Christoph, Lips Klaus
Hahn-Meitner-Institut Berlin, Kekuléstrasse 5, D-12489 Berlin, Germany.
Phys Rev Lett. 2003 Dec 12;91(24):246603. doi: 10.1103/PhysRevLett.91.246603. Epub 2003 Dec 11.
Experimental evidence is presented showing that photocurrents in silicon can be used as highly sensitive readout probes for coherent spin states of localized electrons, the prime candidates for quantum bits in various semiconductor based quantum computer concepts. Conduction electrons are subjected to fast Rabi oscillation induced by means of pulsed electron spin resonance. The collective spin motion of the charge carrier ensemble is reflected by a spin-dependent recombination rate and therefore by the sample conductivity. Because of inhomogeneities, the Rabi oscillation dephases rapidly. However, a microwave induced rephasing is possible causing an echo effect whose intensity contains information about the charge carrier spin state and the coherence decay.
实验证据表明，硅中的光电流可用作局域电子相干自旋态的高灵敏度读出探针，而局域电子是各种基于半导体的量子计算机概念中量子比特的主要候选者。传导电子通过脉冲电子自旋共振受到快速拉比振荡的作用。电荷载流子系综的集体自旋运动由自旋相关的复合率反映，进而由样品电导率反映。由于不均匀性，拉比振荡迅速退相。然而，微波诱导的重新定相是可能的，会产生一种回波效应，其强度包含有关电荷载流子自旋态和相干衰减的信息。
