Microscopic theory of electron spin relaxation in N@C_(60)

摘要

Endohedral N@C_(60) exhibits an extremely long electron spin relaxation time and offers a great potential in storing and processing quantum information. Here, we present a microscopic theory of electron spin relaxation in N@C_(60) The theory combines (1) the spin-orbit interaction of N 2p electrons, which mixes the ground-state ~4S with excited ~2P and ~2D states, and (2) the coupling between the N 2p electrons and C_(60) H_g vibrations, which facilitates transitions between ~2P and ~2D states. The spin relaxation occurs via a two-phonon (Raman) process by absorbing a H_g phonon and emitting another at the (approximately) same frequency. The theory consistently explains measured spin relaxation time T_1 and its temperature dependence, and predicts two independent spin decoherence T_2 constants for ±3/2→ ± 1/2 transitions.