Molecular Engineering of Antiferromagnetic Rings for Quantum Computation

Abstract

The substitution of one metal ion in a Cr-based molecular ring with dominant antiferromagnetic couplings allows the engineering of its level structure and ground-state degeneracy. Here we characterize a Cr7Ni molecular ring by means of low-temperature specific-heat and torque-magnetometry measurements, thus determining the microscopic parameters of the corresponding spin Hamiltonian. The energy spectrum and the suppression of the leakage-inducing S mixing render the Cr7Ni molecule a suitable candidate for the qubit implementation, as further substantiated by our quantum-gate simulations.

Spin dynamics of molecular nanomagnets unravelled at atomic scale by four-dimensional inelastic neutron scattering

“…It is one of the most studied MNMs both for its intrinsic interest and for being the precursor of a large family of heterometallic molecules and supramolecular complexes which are intensively studied for a number of fundamental and applicative issues [8,12,13,[26][27][28]. The spin-Hamiltonian of Cr 8 contains a dominating nearest-neighbor Heisenberg AF exchange and small axial anisotropic terms:…”

“…The magnetic dynamics are characterized by strong quantum fluctuations and this makes MNMs of great interest in quantum magnetism as model systems to investigate a range of phenomena, such as quantum-tunnelling of the magnetization [2][3][4], Néel-vector tunnelling (NVT) [5,6], quantum information processing [7][8][9], quantum entanglement [10][11][12][13] or decoherence [14][15][16]. Besides their fundamental interest, MNMs are also the focus of intense research for the potential technological applications as classical or quantum bits [1,[7][8][9]17] and as magnetocaloric refrigerants [18]. A crucial aspect of the research on MNMs is the understanding of their low-temperature spin dynamics, especially of those aspects which are a direct manifestation of quantum mechanics like the tunneling of the Néel vector in antiferromagnetic rings.…”

Finite-temperature decoherence of spin states in a {Cu3} single molecular magnet

“…At present, chemical manipulation can offer an efficient way to engineer intermolecular couplings and allow for interactions between qubits [26]. The decoherence from the chemical control cannot be easily eliminated because of the permanent interactions with the surrounding [18].…”

Relaxation dynamics in the frustratedCr9antiferromagnetic ring probed by NMR

“…In particular, Cr 7 M rings (M = Zn, Cd, Mn, Ni) are derived from Cr 8 by substitution of one divalent cation M for a trivalent Cr ion 9 . Among them, Cr 7 Ni has been shown to be an excellent candidate to encode qubits 2,[10][11][12][13] . In addition, magnetically-open AF rings like Cr 8 Cd are reference systems to study the microscopic magnetic behaviour of finite AF chains 14 .…”