Transition-Metal Phthalocyanines as Versatile Building Blocks for Molecular Qubits on Surfaces

The search for molecular
or colloidal building units capable of
autonomously organized configurations has been a long-standing endeavor
that has resulted in the development of innovative material categories,
such as metal–organic and covalent organic or long-range molecular
networks. In particular, the possibility of using molecules on surfaces
to create specific architectures, for example, those containing nanostructures
of S = 1/2 molecular spin, can enable versatile quantum
materials and the exploration of future quantum devices. Transition-metal
phthalocyanines are particularly attractive candidates as they are
stable molecules that can host spin-bearing transition-metal ions
in a planar conjugated ring. Here, we use density functional theory
calculations to systematically study electronic and magnetic properties
and hyperfine parameters for the whole series of 3d transition-metal atoms. We perform transport simulations of selected
qubit candidates to further elucidate their suitability for molecular
spin qubits on a surface.