Controlling Spin Interference in Single Radical Molecules

Quantum interference (QI) dominates the electronic properties of single molecules even at room temperature and can lead to a large change in their electrical conductance. To take advantage of this for nanoelectronic applications, a mechanism to electronically control QI in single molecules needs to be developed. In this paper, we demonstrate that controlling the quantum interference of each spin in a stable open-shell organic radical with a large pi-system is possible by changing the spin state of the radical. We show that the counterintuitive constructive spin interference in a meta-connected radical changes to destructive interference by changing the spin state of the radical from a doublet to a singlet. This results in a significant change in the room temperature electrical conductance by several orders of magnitude, opening up new possibilities for spin interference based molecular switches for energy storage and conversion applications.

Automated summary

It has been found that quantum interference in single molecules can be controlled by changing the spin state of stable open-shell organic radicals, resulting in a significant change in their electrical conductance. This discovery opens up new possibilities for spin interference-based molecular switches for energy storage and conversion applications.