Intracage vibrations and Zeeman effect in Y₃N@C₈₀ single-molecule transistors

Clusterfullerenes, which contain a cluster rather than single-atom inclusions, exhibit more complex internal structures and greater degrees of freedom for motion. Trimetallic nitride clusterfullerenes have attracted significant attention due to their diversity and potential applications, among which Y₃N@C₈₀ stands out for its charge-transfer characteristics in electronic excitations, owing to the unique distribution of molecular orbitals near the Fermi level. Here, we have fabricated single-molecule transistor devices using Y₃N@C₈₀. Transport measurements at liquid helium temperature revealed a series of excited state energy levels, which were matched to corresponding vibrational modes through comparison with Raman spectra and density functional theory calculations. Additionally, we measured charge-state-dependent magnetic responses, revealing the electron and spin-filling patterns of the molecular orbitals in Y₃N@C₈₀. These results enhance our understanding of the dynamics and molecular spin-orbit characteristics of clusterfullerenes, indicating their potential for multifunctional applications.