JCMS: Impurity States in Altermagnetic Superconductors

by Andrea Maiani

Monday 3 Mar 2025, 10:30 → 12:00 Europe/Stockholm

Albano 3: 5230 - Xenon (12 seats) (Albano Building 3)

Abstract: Altermagnets are a novel class of magnetic materials distinct from ferromagnets and antiferromagnets, characterized by vanishing net magnetization and unique spin-split band structures – appealing features for exotic quantum phenomena and spintronics applications. This talk explores the interplay between altermagnetism and superconductivity, focusing on how impurities can serve as local probes of altermagnetic superconductors. I will briefly introduce altermagnetic materials, their interplay with superconductivity, and review the basic theory of impurity states in superconductors. Next, I will discuss the phsyics of potential impurities in altermagnetic superconductors, predicting the emergence of spin-polarized subgap states that extend along the crystal axes. These states form degenerate doublets, which can be split by crystal symmetry breaking or a magnetic field aligned with the Néel vector. Their unique spatial and spin properties provide measurable signatures via scanning tunneling microscopy, serving as a hallmark for altermagnetic superconductivity. Finally, I will discuss the interaction between impurities, revealing a position-dependent, spin-selective coupling that enables in-situ control of devices crucial for quantum information processing and topological superconductivity.