Probing the Coherent Spin Dynamics of a Magnetic Impurity in a III-V Semiconductor*

Individual magnetic impurities or small collections of magnetic impurities in III-V semiconductors can be identified via scanning tunneling microscopy (STM)[1,2], their exchange interaction can be measured [3], and they can have remarkably long spin coherence times[4]. Coherent spin dynamics, however, has only been probed in ensemble measurements [4,5]. We describe an approach to explore this coherent spin dynamics through low-field magnetoresistance involving a spin-polarized STM contact. Measurements of the spin coherence time and the local hyperfine interaction should be feasible. We also describe the effect of exchange interactions between magnetic impurities on the magnetoresistance.

[1] J. M. Tang and M. E. Flatté, Phys. Rev. Lett. 92, 047201 (2004).
[2] A. M. Yakunin et al., Phys. Rev. Lett. 92, 216806 (2004).
[3] D. Kitchen et al., Nature 442, 436 (2006).
[4] R. C. Myers et al., Nature Materials 7, 203 (2008).
[5] R. E. George, et al., Phys. Rev. Lett. 110, 027601 (2013).