Toward First Principles Magnon-Phonon Interactions

Collective spin excitations (magnons) in magnetic materials have been intensely investigated in recent years for their potential applications in spintronics and quantum information science. Lattice vibrations (phonons) couple with magnons and set an intrinsic limit to their lifetimes and coherent transport. In this talk, we will present an approach for computing magnon-phonon interactions from first principles. This method combines ab initio electron-phonon interactions with magnon wave functions obtained from the finite-momentum Bethe-Salpeter equation, leveraging an interface between the YAMBO and PERTURBO codes. We will present illustrative calculations of magnon-phonon coupling and magnon lifetimes due to phonons in two-dimensional (anti)ferromagnetic materials. Extensions of this formalism will also be discussed.