An international research team, with the participation of the Institute of Molecular Science (ICMol) of the University of Valencia, has achieved spin-electric control in molecular nanomagnets. This fact offers great advantages when preparing quantum devices based on magnetic molecules. The work is published in the journal Nature Physics.

For some time, science has been looking for viability for the development of devices based on quantum bits (qubits), basic units of a quantum computer. In magnetic materials, a possible qubit is provided by the spin-quantum property of elementary particles such as the electron. In this context, the electrical control of spin offers important advantages for the development of quantum computing and, in general, quantum technologies.

An international research team with the participation of ICMol has taken a step forward in this field by achieving this challenge using molecular nanomagnets.

“Experimentally, we put a glass formed by these molecular nanomagnets between two electrodes separated by 2 mm; we apply a voltage of 200 V for a few microseconds and, with the electric field generated, we control the quantum state of the molecules, which opens a way independent of communication between them”, points out Alejandro Gaita-Ariño, researcher at ICMol. “The fact that electronic circuits are so well developed, even at the nanotechnological level, serves as a model for us to prepare quantum devices based on magnetic molecules,” he adds.

The study now published in Nature Physics analyses a molecular nanomagnet in which a small structural distortion establishes transitions between quantum states, called ‘atomic clock’ states, which are protected from magnetic noise. This minimises inconsistency and thus controls the information to an unprecedented degree. The researchers show coherent electrical control of the quantum spin state and exploit it to independently manipulate the two magnetically identical but opposite-oriented molecules. “This allows us to take advantage for the first time of the potential of the electric field as a key player for qubit control”, says team member José J. Baldoví. “The advantage of our approach is that, contrary to what happens with magnetic fields, an electric field can control quickly and at the nanoscale the quantum state of spin qubits”, says Eugenio Coronado, ICMol researcher and also a member of the team.

Estos descubrimientos allanan el camino para el uso de los espines moleculares en las tecnologías cuánticas. Además de científicos de la Universitat de València, participan en el estudio investigadores de la Universidad de Oxford. La investigación se produce en el marco del proyecto FATMOLS (FAult Tolerant MOLecular Spin processor), llevado a cabo por el único consorcio europeo que trabaja en el desarrollo de la computación cuántica basada en el magnetismo molecular y que cuenta con financiación de las ayudas europeas FET-Open Challenging Current Thinking. These findings pave the way for the use of molecular spins in quantum technologies. In addition to scientists from the University of Valencia, researchers from the University of Oxford are taking part in the study. The research is part of the FATMOLS (FAult Tolerant MOlecular Spin processor) project, carried out by the only European consortium working on the development of quantum computing based on molecular magnetism and funded by the FET-open Challenging Current Thinking European subsidies. 

Reference:

Quantum coherent spin-electric control in a molecular nanomagnet at clock transitions. Junjie Liu, Jakub Mrozek, Yan Duan, Aman Ullah, José J. Baldoví, Eugenio Coronado, Alejandro Gaita-Ariño, Arzhang Ardavan. Nature Physics
DOI: https://www.nature.com/articles/s41567-021-01355-4