Quantum computing with molecular magnets

Quantum tunneling of two coupled single-molecular magnets

Two single-molecule magnets are coupled antiferromagnetically to form a supramolecule dimer. We study the coupling effect and tunneling process by means of the numerical exact diagonalization method, and apply them to the recently synthesized supramoleculer dimer [Mn4]2. The model parameters are calculated for the dimer based on the tunneling process. The absence of tunneling at zero field and ...

Quantum fluctuations and long-range order in molecular magnets

We review our studies of the effect of transverse fields on the susceptibility and magnetization of single crystals of the prototype single molecule magnet (SMM), Mn12-acetate, and of a new high-symmetry variant, Mn12-acetate–MeOH. SMM single crystals can exhibit long range ferromagnetic order associated with intermolecular dipole interactions. Transverse fields increase quantum spin fluctuatio...

Quantum-tunneling-induced Kondo effect in single molecular magnets.

We consider transport through a single-molecule magnet strongly coupled to metallic electrodes. We demonstrate that, for a half-integer spin of the molecule, electron and spin tunneling cooperate to produce both quantum tunneling of the magnetic moment and a Kondo effect in the linear conductance. The Kondo temperature depends sensitively on the ratio of the transverse and easy-axis anisotropie...

Random quantum magnets with broad disorder distribution

We study the critical behavior of Ising quantum magnets with broadly distributed random couplings (J), such that P (lnJ) ∼ | ln J |, α > 1, for large | lnJ | (Lévy flight statistics). For sufficiently broad distributions, α < αc, the critical behavior is controlled by a line of fixed points, where the critical exponents vary with the Lévy index, α. In one dimension, with αc = 2, we obtaind seve...

Quantum Magnets 2015