Electric fields represent an ideal means for controlling spins at the nanoscale and, more specifically, for manipulating protected degrees of freedom in multispin systems. Here we perform low-temperature magnetic far-IR spectroscopy on a molecular spin triangle (Fe3) and provide initial experimental evidence suggesting spin-electric transitions in polynuclear complexes. The co-presence of electric- and magnetic-dipole transitions, allows us to estimate the spin-electric coupling. Based on spin Hamiltonian simulations of the spectra, we identify the observed transitions and introduce the concept of a generalized exchange qubit. This applies to a wide class of molecular spin triangles, and includes the scalar chirality and the partial spin sum qubits as special cases.

Institut de Chimie de Strasbourg Université de Strasbourg 4 rue Blaise Pascal CS 90032 F 67081 Strasbourg France

Institute of Physics Charles University Ke Karlovu 5 Prague Czech Republic

Istituto Nanoscienze CNR Centro S3 via Campi 213a Modena 41125 Italy

Laboratoire National des Champs Magnétiques Intenses CNRS UGA UPS INSA EMFL 25 rue des Martyrs Grenoble France

Scientific Computing Theory and Data Division Paul Scherrer Institute Villigen PSI Switzerland

Nat Commun. 2025 Mar 3;16(1):2120. doi: 10.1038/s41467-025-57502-5. PubMed

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