Optical signals of spin switching using the optical Stark effect in a Mn-doped quantum dot

Abstract

The optically induced spin dynamics of a single Mn atom embedded into a single semiconductor quantum dot can be strongly influenced by using the optical Stark effect. The exchange interaction gives rise to simultaneous spin flips between the quantum dot electron and Mn. In the time domain these flips correspond to exchange induced Rabi oscillations, which are typically off-resonant. By applying a detuned laser pulse, the states involved in the flipping can be brought into resonance by means of the optical Stark effect increasing the amplitude of the Rabi oscillations to one. In this paper we study theoretically how this spin dynamics can be monitored in time-resolved spectroscopy. In the spectrum the exchange interaction leads to a splitting of the exciton line into six lines, each corresponding to one of the six Mn spin states. The dynamical behavior of the Mn spin is reflected by the strength of the individual lines as a function of time. When an off-resonant optical pulse is applied the spectral positions of the lines shift, but still the flipping dynamics is visible.

Dynamics of a Mn spin coupled to a single hole confined in a quantum dot

“…In different QD systems with a larger hole confinement and weaker valence-band mixing one could expect a spin memory controlled by the electrically tunable magnetic anisotropy of the hole-Mn complex. Nevertheless, a relaxation time in the μs range is sufficient to exploit these positively charged Mn-doped QDs for an optical ultrafast coherent control of the Mn spin [34,35]. Pulsed resonant excitation could be used to create and annihilate the positively charged exciton and deterministically control the electron-Mn flip-flops to manipulate the Mn spin.…”

Magneto-Optical Stark Effect in Fe-Doped CdS Nanocrystals

“…The use of the spin degree of freedom of an electron, specifically in a system with strong spin-orbit coupling leading to ultrafast spin selectivity, 1 promises to lead to enhancement of data processing speed and integration densities, allowing a reduction in electrical power consumption in comparison to the conventional electronic devices. [2][3][4] However, the most important parameter for potential applications in spintronics is the presence of multiple low energy spin configurations of the transition metal ions. Hence, even though iron is naturally magnetic, so far there has been no demonstration of spintronic-like states in Fe 2+ doped simple II-VI semiconductors.…”

“…The combination of nanotechnologies with quantum physics uses the power of the laws of physics for practical purposes. The use of the spin degree of freedom of an electron, specifically in a system with strong spin–orbit coupling leading to ultrafast spin selectivity, promises to lead to enhancement of data processing speed and integration densities, allowing a reduction in electrical power consumption in comparison to the conventional electronic devices. − However, the most important parameter for potential applications in spintronics is the presence of multiple low energy spin configurations of the transition metal ions. Hence, even though iron is naturally magnetic, so far there has been no demonstration of spintronic-like states in Fe 2+ doped simple II–VI semiconductors. , However, the spin of the Fe dopant is very sensitive to the local environment, and CdS nanocrystals (NCs) have the potential to strongly hybridize with magnetic ions, beyond the classical description of diluted magnetic semiconductors. , Until now, however, the power of spatial confinement of the wave function as well as the role of dopant–host interactions, free of dopant–dopant interactions, have not been explored.…”

Time-resolved pump-probe signals of a continuously driven quantum dot affected by phonons

“…In the numerical solution, the probe pulse is modelled as a Gaussian pulse with a width of 10 fs. The probe polarization p P is obtained by filtering the phase of the probe pulse using a Fourier expansion [35][36][37]. In the analytical solution the probe pulse is assumed to be a δ-pulse with a phase ϕ.…”