Molecular Magnetic Quantum Materials: Connecting DFT calculations to experiments

Magnetic molecules are unique among nano-magnets because of their monodispersity and stability. We investigate fundamental physical properties of single molecules, 1D chains, 2D sheets, and 3D crystals, as well as cluster crystallines and their interactions with substrates in heterogenous junctions with focus on physical processes critical to quantum information sciences and next generation electronics. The inherent large number of degrees of freedom in molecular systems brought by ligand fields and the complexity of 3d transition metal oxide cores expands greatly the tunability of the parameter space for magnetic anisotropy, inter-ion spin couplings, and strain induced magnetoelectric couplings. The relevant energy scales range from micro electron volts to electron volts. The need for accurate parameter estimation spanning six orders of magnitude presents a grand challenge in modeling for molecular magnetic quantum materials. In this talk, I give an overview on our effort bringing first-principles calculations based on density functional calculations of energetics such as binding energy, phonon energy, anisotropy energy into many-body and dynamic studies using the density matrix method, model Hamiltonians, and Monte-Carlo simulations. This approach connects first-principles theory to experiments across a broad range of problems, including spin coupling between qub(d)its, phases and phase diagrams in spin-crossover materials, manipulation and detection of entangled spin states, and the Dzyaloshinskii-Moriya interaction in magnetic molecules, and electron spin decoherence due to interaction with molecular environments. Finally, I will briefly discuss the role of computationally based theoretical prediction: the finding of Majorana zero energy state and the road map towards computational synthesis of magnetic molecules.