title: Molecular qubits based on potentially nuclear-spin-free nickel ions.
abstract: Molecular qubits with the longest coherence times thus far are based on nuclear-spin-carrying central ions. These nuclear spins can cause quantum state leakage, which is detrimental to quantum algorithm performance. We present two novel molecular qubits based on potentially nuclear spin-free Ni in the formal oxidation state 3+. (d20-PPh4)[Ni(mnt)2] (Ni-mnt, mnt2-= maleonitrile-1,2-dithiolate) possesses a coherence time of up to 38.7 μs at 7 K. Functionalization of the dithiolate ligand decreases the coherence time by a factor of only four in (HNEt3)[Ni(dip)2] (Ni-dip, dip2-= 3-(diphenylphosphoryl)-methylbenzene-1,2-dithiolate), indicating that monoanionic Ni-dithiolene complexes are promising and robust building blocks for polynuclear molecular qubit gates.
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany. slageren@ipc-uni-stuttgart.de.
authors.forename: K
authors.initials: K
authors.lastname: Bader
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
authors.forename: S H
authors.initials: SH
authors.lastname: Schlindwein
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Gudat
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany. slageren@ipc-uni-stuttgart.de and Center for Integrated Quantum Science and Technology (IQST), Stuttgart/Ulm, Germany.
authors.forename: J
authors.identifier: http://orcid.org/0000-0002-0855-8960
authors.initials: J
authors.lastname: van Slageren