T o M P : Theory of Materials Properties

The fifth PhD from ToMP! Congratulations Dr. Sugandha Saxena!

Six from the group received their degrees in yesterday's convocation at IISER Bhopal. Vivek, Ramsamoj, and Suman (in absentia) received their PhD degrees, while Barishan, Devika (in absentia), and Yugandhara (in absentia) received their BS-MS degrees. A moment of pride for all of us! Our count so far: 4 PhDs, 9 MSs. The present group members appear motivated by the alumni's achievements!

Ab tak 4! Congratulations, Dr. Ramsamoj Kewat, on successfully defending your PhD thesis!

We are happy to announce that today Suman Rooj successfully defended his PhD thesis. Congratulations Dr. Suman Rooj.

https://link.aps.org/doi/10.1103/PhysRevB.111.064413
Spin-orbit interaction, combined with inversion asymmetry, leads to a spin-splitting and helical spin texture, known as the Rashba or Dresselhaus effect, depending on the nature of inversion asymmetry. In the context of perovskite oxide heterostructures, Rashba or Dresselhaus effects or their combination are ubiquitous. Combined with antiferromagnetism in a suitable material, such spin textures may lead to spin-orbit torque and anisotropic magnetoresistance, paving the way for technologies based on antiferromagnetic spintronics. Taking LaAlO3|SrIrO3|SrTiO3 as an example and constraining the undistorted structure to preserve inversion symmetry, we map the nature of inversion asymmetry arising due to progressive structural distortion to the type of spin-orbit interaction: Rashba interaction due to structure inversion asymmetry and combined Rashba-Dresselhaus interaction due to both structure and bulk inversion asymmetry. We obtain the spin texture directly from our DFT calculation and compare them with the model spin texture, showing agreement. Our work illustrates how commonly occurring structural distortions in perovskite oxides correspond to different types of Rashba-like spin-orbit interactions. Nirmal Ganguli, Jayita Chakraborty

Altermagnetism emerges as one of the most intriguing and technologically promising aspects of the magnetic properties in materials. Although they existed forever, the properties of altermagnets have recently come to light, calling for a detailed understanding. With examples of BiFeO3 and CaMnO3 in orthorhombic Pnma structure, we demonstrate how global asymmetry may lead to the realization of altermagnets, how local symmetries may still preserve spin degeneracy in some parts of the Brillouin zone, and in which parts of the Brillouin zone spin splitting is expected. Further, we note that spin-orbit interaction may lead to a noncollinear arrangement of the spin and a weak ferromagnetism if the corresponding magnetic space group allows for the same, leading to an anomalous Hall conductivity in the system. Our work helps develop a thorough understanding of altermagnets and paves the way for their technical applications.
https://doi.org/10.1103/PhysRevB.111.014434

Congratulations! Dr. Vivek Kumar! ToMP wishes you all the best for your future! Second PhD from ToMP.

Congratulations! Dr. Avishek Singh!