Electronic statistics on demand: Bunching, antibunching, positive, and negative correlations in a molecular spin valve

One of the long-standing goals of quantum transport is to use the noise, rather than the average current, for information processing. However, achieving this requires on-demand control of quantum fluctuations in the electric current. In this paper, we demonstrate theoretically that transport through a molecular spin valve provides access to many different statistics of electron tunneling events. Simply by changing highly tunable parameters, such as electrode spin polarization, magnetization angle, and voltage, one is able to switch between Poisson behavior, bunching and antibunching of electron tunnelings, and positive and negative temporal correlations. The molecular spin valve is modeled by a single spin-degenerate molecular orbital with local electronic repulsion coupled to two ferromagnetic leads with magnetization orientations allowed to rotate relative to each other. The electron transport is described via Born-Markov master equation and fluctuations are studied with higher-order waiting time distributions. For highly magnetized parallel-aligned electrodes, we find that strong positive temporal correlations emerge in the voltage range where the second transport channel is partially open. These are caused by a spin-induced electron-bunching, which does not manifest in the stationary current alone.

Automated summary

This paper investigates the statistical behavior of electron transport through a molecular spin valve, demonstrating that different behaviors such as Poisson behavior, bunching, antibunching, and positive and negative temporal correlations can be achieved by tuning parameters. The study finds that strong positive temporal correlations emerge in the voltage range where the second transport channel is partially open, due to spin-induced electron bunching.