Electron spin coherence in metallofullerenes: Y, Sc and La@C82

TL;DR

This study demonstrates that metallofullerenes like Y, Sc, and La@C82 exhibit electron spin coherence times exceeding 200 microseconds, significantly longer than previously reported, due to reduced relaxation mechanisms.

Contribution

It provides the first detailed measurement of long electron spin coherence times in metallofullerenes, highlighting their potential for quantum technologies.

Findings

Maximum T2 > 200 microseconds in deuterated o-terphenyl

Relaxation mechanisms include vibrational modes, spin-orbit coupling, nuclear spins

T2 times are over 100 times longer than prior reports

Abstract

Endohedral fullerenes encapsulating a spin-active atom or ion within a carbon cage offer a route to self-assembled arrays such as spin chains. In the case of metallofullerenes the charge transfer between the atom and the fullerene cage has been thought to limit the electron spin phase coherence time (T2) to the order of a few microseconds. We study electron spin relaxation in several species of metallofullerene as a function of temperature and solvent environment, yielding a maximum T2 in deuterated o-terphenyl greater than 200 microseconds for Y, Sc and La@C82. The mechanisms governing relaxation (T1, T2) arise from metal-cage vibrational modes, spin-orbit coupling and the nuclear spin environment. The T2 times are over 2 orders of magnitude longer than previously reported and consequently make metallofullerenes of interest in areas such as spin-labelling, spintronics and quantum computing.