Effects of magnetisation patterns and emergent monopoles on the electronic structure of spin ice Dy$_2$Ti$_2$O$_7$ in photoabsorption measurements

Spin ice, a frustrated magnetic system, exhibits several unusual features, including a highly degenerate (spin liquid) ground state and emergent magnetic monopole excitations. While experimental signatures of these properties have been observed in magnetisation and neutron scattering measurements, their effect on the electronic structure has not been explored. In this project, a simplified model for the electronic structure of spin ice Dy$_2$Ti$_2$O$_7$ was developed to investigate the effects of the magnetic pattern of the localised Dy f-moments on the (insulating) band structure of the Ti d-electrons. Whereas a number of effects are potentially at play, including Aharonov-Bohm and Berry phases, we find that most of them have a largely negligible effect, with the exception of scattering due to the induced electric dipole moment on tetrahedra that host monopoles. This results in a perturbation of the band structure that is linear in the density of monopoles and may be observable in an experimentally measurable change in the tail of the photoabsorption spectrum.