Magneto-orbital effect without spin-orbit interactions in a noncentrosymmetric zeolite-templated carbon structure

A peculiar manifestation of orbital angular momentum is proposed for a zeolite-templated carbon system, C ₃₆H ₉. The structure, being a network of nanoflakes in the shape of a "pinwheel," lacks inversion symmetry. While the unit cell is large, the electronic structure obtained with a first-principles density-functional theory and captured as an effective tight-binding model in terms of maximally localized Wannier functions, exhibits an unusual feature that the valence band top comes from two chiral states having orbital magnetic momenta of ±1. The noncentrosymmetric lattice structure then makes the band dispersion asymmetric, as reminiscent of, but totally different from, spin-orbit systems. The unusual feature is predicted to imply a current-induced orbital magnetism when holes are doped.