The Joint Condensed Matter Seminar (JCMS) series is organised by KTH Royal Insitute of Technology, Nordita, and Stockholm University.
On Monday, March 3rd, 2025 from 11 am to 12 am we will host a seminar by Andrea Maiani from Nordita.
Impurity States in Altermagnetic Superconductors
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.