"Congratulations to Dr. Sharma S. R. K. C. Yamijala for Receiving the Young Faculty Recognition Award"

Minimal Models for Altermagnetism

The discovery of a new, third fundamental class of collinear magnets with zero net magnetization, but with unconventional spin-polarized band structure, expanded the known classes of ferromagnets and antiferromagnets. The third class, called altermagnet is characterized by spin configurations that remain invariant under a combination of two symmetry operations: time reversal, which flips the spins, and a lattice rotation, which can be proper or improper [1]. This leads to physical properties that are commonly known from ferromagnets, but with a vanishing total magnetization opening the avenue for research directions as for example spintronics, strong correlations and superconductivity, to topological phases of matter [2].
Motivated by the fact that all proposed altermagnets have paramagnetic states with multiple magnetic ions in the unit cell, we develop a class of realistic minimal models for altermagnetism through a comparative analysis of the magnetic atom Wyckoff site symmetry and the space group symmetry. Specifically, we develop electronic models for all centrosymmetric space groups with magnetic atoms occupying inversion symmetric Wyckoff positions with multiplicity two. These forty models include monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic materials and describe d-wave, g-wave, and i-wave altermagnetism. We further define and examine an altermagnetic susceptibility and mean field instabilities within a Hubbard model to reveal that these models have altermagnetic ground states. We shed insight on why most altermagnets form in non-symmorphic space groups. We also provide the symmetry-required form of the spin-orbit coupling and show it yields a Berry curvature that is linear in this coupling for all forty models. We apply our models to representative cases of RuO2, MnF2, FeSb2, κ-Cl, CrSb, and MnTe [3].

[1] Libor Šmejkal, Jairo Sinova, and Tomas Jungwirth, Phys. Rev. X 12, 031042 (2022)
[2] Libor Šmejkal, Jairo Sinova, and Tomas Jungwirth, Phys. Rev. X 12, 040501 (2022)
[3] Mercè Roig, Andreas Kreisel, Yue Yu, Brian M. Andersen, Daniel F. Agterberg, arXiv:2402.15616 (2024)

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CAMMD Annual Newsletter 2023-2024

Best Poster Presentation

Mr. Arijit Mandal (PMRF) has received the Best Poster Presentation award in the Workshop and International Conference on Electronic Structure Theory of Emergent Spin-Orbit Driven Phenomena (ESTESODP 2024), hosted by IIT Bombay from November 11 to 15, 2024

Institute Research Award

"Congratulations to Abhijitha V G for Receiving “Institute Research Award” in recognition of excellent PhD work - 2024.

Best PhD Thesis

"Congratulations to Dr. Mayank Gupta for receiving the A L Lashkar Prize for Best PhD Thesis (in Physics) for the year 2023-24."

Best Poster Presentation

Congratulating Ayusmin Panda for presenting our research paper on "Enhancement of Quantum Efficiency in Perovskite Solar Cells through Whispering Gallery Modes from Titanium Oxide Micro-resonators" at the Symposium of SPIE Photonics Europe- 2024.

Best Poster Presentation

Mr. Arijit mandal received "Best Poster Presentation" on "Electrical Tuning of Topological Hall Effect in Skyrmion Crystals" at the 4th National Conference on Physics of Strongly Correlated Electron Systems (PSCES) 2024, which was organized at IISER Bhopal, Madhya Pradesh, India.

Best Poster Presentation

Mr. Jatin Kumar Bidika received "Best Poster Presentation" on "The Curious Non-Trivial Magnetic Ordering of Cuprates with A-site Ordered Perovskite Structure: CaCu3B4O12" at the QMAT-2023 conference, which was organized at NISER Bhubaneswar, Odisha.