Electron-nuclear coherent spin oscillations probed by spin-dependent recombination

Abstract

We demonstrate the detection of coherent electron-nuclear spin oscillations related to the hyperfine interaction and revealed by the band-to-band photoluminescence (PL) in zero external magnetic field. On the base of a pump-probe PL experiment we measure, directly in the temporal domain, the hyperfine constant of an electron coupled to a gallium defect in GaAsN by tracing the dynamical behavior of the conduction electron spin-dependent recombination to the defect site. The hyperfine constants and the relative abundance of the nuclei isotopes involved can be determined without the need of electron spin resonance technique and in the absence of any magnetic field. Information on the nuclear and electron spin relaxation damping parameters can also be estimated from the oscillations damping and the long delay behavior.

Spin Polarization Oscillations and Coherence Time in the Random Interaction Approach

“…was plotted in Figure 1 on top of the spin polarization calculated in [19]. Our calculation of the spin polarization in Figure 1 was for = 300K, = 10 9 × s −1 , with = 0.28, and = 2.58 × 10 10 s −1 .…”

“…Attempts to solve completely the models for dissipative twostate systems are generally faced with mathematical complexities. Examples vary from entangled differential equations in master equation approaches [11,19] to perturbative calculations in the 'spin-boson' [14] and the rotating-wave" approximation [16]. Recently the master equation approach [19] was applied to describe the evolution of the electronic and nuclear spin polarizations of interstitial gallium defects, which behave as paramagnetic centers in dilute (Ga,N)As semiconductor that selectively capture electrons with opposite spin, and block the recombination of conduction band electrons with the same spin (which lead to an increase of the lifetime of conduction electrons and bound electrons from picoseconds to nanoseconds).…”

“…Examples vary from entangled differential equations in master equation approaches [11,19] to perturbative calculations in the 'spin-boson' [14] and the rotating-wave" approximation [16]. Recently the master equation approach [19] was applied to describe the evolution of the electronic and nuclear spin polarizations of interstitial gallium defects, which behave as paramagnetic centers in dilute (Ga,N)As semiconductor that selectively capture electrons with opposite spin, and block the recombination of conduction band electrons with the same spin (which lead to an increase of the lifetime of conduction electrons and bound electrons from picoseconds to nanoseconds). The intricacy of this approach expressed through almost a hundred of coupled nonlinear differential equations (with assumptions on the dissipative interactions) reminds us of the 'much too intractable (intermediate results) of the spin-boson model' [15].…”

Сверхтонкое Взаимодействие И Рекомбинация Шокли--Рида--Холла В Полупроводниках

“…С учетом спиновой релаксации и наличия двух изотопов галлия получаем вместо (8) В [13] функция F( t) аппроксимировалась экспонентой exp(− t/T * 2 ) с подгоночным временным параметром T * 2 . Предсказанные спиновые биения обнаружены в совместной экспериментально-теоретической работе [20] (рис. 3).…”

“…В магнитном поле 65 мТл размах спиновых биений (кривая 2) уменьшается незначительно по сравнению с биениями в отсутствие поля (кривая 1). Это не согласуется с экспериментальным наблюдением сильного подавления осцилляций уже в поле 65 мТл [20], что требует дополнительного изучения.…”