In the same way that a photon can be seen as the quasiparticle that carries the energy of an electromagnetic wave, magnons are quasiparticles that propagate the energy of a spin wave. Spin waves are low-energy excitations that arise from the correlated motion of electron-hole pairs with opposite spins. Theoretically, they can be studied within many-body perturbation theory and the spin-wave spectrum, or “magnonic spectrum” (energy vs. momentum), can be calculated from first-principles.
Recently, a new class of magnetic order has been discovered that is distinct from ferromagnetism and antiferromagnetism. This new phase has been termed “altermagnetism”. Altermagnets show compensated magnetic order, like antiferromagnets, but also a novel spin-polarization alternating in momentum space. Altermagnets thus exhibit properties characteristic of ferromagnets and antiferromagnets, but also new unique properties. These properties make these materials very attractive in fields like spintronics, multiferroics, magnonics, topological matter, or superconductivity.
It is known that the magnonic spectrum of ferromagnets and antiferromagnets look different. But what does the magnonic spectrum of an altermagnet look like? In this project, you can answer this and other questions related to magnons in altermagnets by performing calculations of the magnonic spectrum of the altermagnet CrSb, using a Bethe-Salpeter equation for the magnetic response, as implemented in the code SPEX (www.flapw.de/spex).
The group Ab Initio Quantum Materials (AIQM) is part of the Condensed Matter Theory group at the Institute of Physics (IoP) of the UvA. The research will be embedded in a stimulating international environment, and it will involve various local and international collaborations including experimental groups at the IoP and the developers of the codes from Forschungszentrum Juelich, Germany. This project is for you if you are interested in numerical simulations, condensed matter theory, functional materials, and you have a solid background on electromagnetism and quantum mechanics.
