# Near-perfect spin filtering and negative differential resistance in an Fe(II)S complex

## TL;DR

This study demonstrates that an iron(II)sulfur complex acts as an almost perfect spin filter with negative differential resistance at low bias, highlighting its potential for nanoelectronic and spintronic devices.

## Contribution

The paper provides a theoretical demonstration of near-perfect spin filtering and negative differential resistance in an Fe(II)S complex, a novel finding for molecular spintronics.

## Key findings

- Spin-filtering efficiency exceeds 99%.
- Negative differential resistance appears at low bias voltage.
- Conductance changes are linked to molecular orbital shifts.

## Abstract

Density functional theory and nonequilibrium Green's function calculations have been used to explore spin-resolved transport through the high-spin state of an iron(II)sulfur single molecular magnet. Our results show that this molecule exhibits near-perfect spin filtering, where the spin-filtering efficiency is above 99%, as well as significant negative differential resistance centered at a low bias voltage. The rise in the spin-up conductivity up to the bias voltage of 0.4 V is dominated by a conductive lowest unoccupied molecular orbital, and this is accompanied by a slight increase in the magnetic moment of the Fe atom. The subsequent drop in the spin-up conductivity is because the conductive channel moves to the highest occupied molecular orbital which has a lower conductance contribution. This is accompanied by a drop in the magnetic moment of the Fe atom. These two exceptional properties, and the fact that the onset of negative differential resistance occurs at low bias voltage, suggests the potential of the molecule in nanoelectronic and nanospintronic applications.