Manipulation and readout of spin states of a single-molecule magnet by a spin-polarized current

TL;DR

This paper demonstrates how to manipulate and read out the spin states of a single-molecule magnet using spin-polarized currents, with potential applications in nanoscale memory devices.

Contribution

It introduces a method to control and detect spin states in a single-molecule magnet via electrical means, highlighting the effects of tunneling parameters and bias voltage.

Findings

Switching time depends on tunneling gap and transition energy, tunable by gate voltage.

Readout of spin states is possible by analyzing the current's time derivative when bias is off.

Tunneling strength and electrode coupling asymmetry significantly influence switching time.

Abstract

Single-molecule memory device based on a single-molecule magnet (SMM) is one of the ultimate goals of semiconductor nanofabrication technologies. Here, we study how to manipulate and readout the SMM's two spin-state of stored information that characterized by the maximum and minimum average value of the $Z$-component of the total spin of the SMM and the conduction-electron, which are recognized as the information bits "$1$" and "$0$". We demonstrate that the switching time depends on both the sequential tunneling gap $\varepsilon_{se}$ and the spin-selection-rule allowed transition-energy $\varepsilon_{trans}$, which can be tuned by the gate voltage. In particular, when the external bias voltage is turned off, in the cases of the unoccupied and doubly-occupied ground eigenstates, the time derivative of the transport current can be used to read out the SMM's two spin-state of stored information. Moreover, the tunneling strength of and the asymmetry of the SMM-electrode coupling have a strong influence on the switching time, but that have a slight influence on the readout time that being on the order of nanoseconds. Our results suggest a SMM-based memory device, and provide fundamental insight into the electrical controllable manipulation and readout of the SMM's two spin-state of stored information.