Electrons in an iron-based molecule have been spotted crossing between four different spin states in less than 50 fs, which is the fastest ever observation of such a transition. The measurements were made by researchers in Switzerland, who say that the speed of the transition means that the electrons jump directly from the initial low-spin state to the final high-spin state without going through any intermediate states. A new theoretical model is now needed to describe such rapid transitions, and their discovery has implications for future devices based on the spin of the electron.


electron spin fs


Electrons in atoms, molecules and solids exist in different spin states, and electrons can make transitions between these states. Spintronics makes use of such states to process and store information, and has the potential to deliver devices that are smaller and more energy efficient than conventional electronics. These states are quantum-mechanical in nature and therefore could also be used as building blocks for quantum computers, which could out-perform conventional computers on certain tasks. But before the full potential of spintronics can be realized, researchers need to gain a better understanding of the nature of spin transitions – or crossovers, as they are called in iron-based molecules.