This project focuses on the derivation of macroscopic spin Hamiltonian starting from a multiband Hubbard model in the presence of spin-orbit and Coulomb exchange interactions for novel magnetic materials. Systems of interest include frustrated quantum magnetic materials such as antiferromagnetic spins on a tetragonal lattice (i.e., SR₂CuCl₂O₂, R₂CuO₄) or Kagome lattices, as well as high-spin magnetic molecules (i.e., Fe₈ and Mn₁₂-ac). Some of the computational techniques that we use are degenerate perturbation theory, exact numerical diagonalization, 1/S expansion within interacting and non-interacting spin-wave expansion. Various magnetic properties such as ground-state spin configuration, spin dynamics due to thermal and quantum fluctuations, spin waves, and gaps, are calculated from the derived magnetic Hamiltonian and compared with the neutron scattering measurements.

 

Keywords:

Neutron scattering; Polarization (spin alignment); Rare-earth elements; Transition metals;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants