In a paper published in Nature Physics this week, a team from Oxford’s Department of Physics, in collaboration with Institute of Molecular Science (ICMol) at the University of Valencia, has demonstrated electrical control of quantum spins in molecular nanomagnets.
Traditionally, quantum spins are controlled using magnetic fields because the spin carries an associated magnetic moment. Electrical control offers important advantages in the design of integrated quantum-spin-based devices because it is possible to control electric fields on shorter length scales than magnetic fields. This result therefore represents a milestone on the path towards molecular quantum technologies.
The paper reports experiments on a molecular nanomagnet in which a small structural distortion gives rise to a transition between quantum spin states that is insensitive to magnetic field fluctuations; this is known as a ‘clock transition’. The investigators showed how an applied electric field adjusts the distortion, permitting an unprecedented degree of control over the quantum spin state superposition. A theoretical analysis of the process reveals design criteria for future electrically-controllable molecular systems, and generates new insights into the important general question of the coupling between magnetic and electric properties in functional materials.
The investigators are supported by RCUK through the Engineering and Physical Sciences Research Council, The Royal Society, and the EU through the Horizon 2020 Future and Emerging Technologies programme.
Quantum coherent spin-electric control in a molecular nanomagnet at clock transitions, Junjie Liu et al, Nature Physics, 14 October 2021