Endohedral Metallofullerene as Molecular High Spin Qubit: Diverse Rabi Cycles in Gd₂@C₇₉N

An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover’s algorithm can be implemented in such systems. Dimetallic aza[80]­fullerenes M₂@C₇₉N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd₂@C₇₉N for the first time. This molecular magnet with a collective high-spin ground state (<i>S</i> = 15/2) generated by strong magnetic coupling (<i>J</i>_Gd‑Rad = 350 ± 20 cm^–1) has been unambiguously validated by magnetic susceptibility experiments. Gd₂@C₇₉N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 μs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover’s searching algorithm proposed by Leuenberger and Loss