Many-Spin Effects and Tunneling Properties of Magnetic Molecules

TL;DR

This paper presents a realistic many-spin calculation of tunneling splittings in Mn12 molecular magnets, revealing significant differences from single-spin models and advancing understanding of quantum tunneling in complex magnetic molecules.

Contribution

It provides the first accurate many-spin theoretical analysis of tunneling splittings in Mn12 molecules, improving upon single-spin approximations.

Findings

Many-spin effects significantly alter tunneling splittings.

Ground state splitting differs by a factor of five between models.

The study covers energy intervals from 100 K to 10^{-12} K.

Abstract

Spin tunneling in molecular magnets has attracted much attention, however theoretical considerations of this phenomenon up to now have not taken into account the many-spin nature of molecular magnets. We present, to our knowledge, the first successful attempt of a realistic calculation of tunneling splittings for Mn$_{12}$ molecules, thus achieving a quantitatively accurate many-spin description of a real molecular magnet in the energy interval ranging from about 100 K down to 10$^{-12}$ K. Comparison with the results of the standard single-spin model shows that many-spin effects affect the tunneling splittings considerably. The values of ground state splitting given by single-spin and many-spin models differ from each other by a factor of five.