Welcome to the official webpage of ToMP: Theory of Materials Properties. We are a research group in the Department of Physics, IISER Bhopal, working on condensed matter physics and materials science using theoretical and numerical techniques. This page gives a glimpse of ourselves and our activities.
Using theoretical techniques and numerical simulations primarily based on density functional theory and Monte Carlo simulations, we study electronic structure, magnetism, and optical properties of nanomaterials and heterojunctions. We are primarily interested in the role of spin-orbit interaction at surfaces and interfaces with restricted symmetry. Below are some of our research interests:
Rashba-like spin-orbit interaction holds enormous promise for spintronics and other quantum technologies, making it one of the most sought-after research topics. Correctly qualifying the nature of the interaction and the associated spin texture in materials of interest is the key to its technological applications. KTaO3 is an exciting material in the context of oxide electronics that hosts a robust Rashba-like interaction. We consider a thin and a thick slab of this polar material and find the former to be an insulator while the latter to be a conductor at the (001) surfaces; an electrostatic model explains our observation and predicts a critical thickness of the slab beyond which the conducting nature sets in. Subsequently, we directly identify the Rashba-like split bands, the corresponding three-dimensional bands, isoenergetic contours, and spin texture on a plane from our DFT calculations. In contrast with the splitting of bands in the momentum space helping us to guess a Rashba-like interaction, the spin texture plotted along with the isoenergetic contours provides a confirmatory test of the presence of only linear Rashba interaction in the system. Besides understanding the physical properties of KTaO3, our work demonstrates a method for unequivocally establishing the exact nature of Rashba-like spin-orbit interactions.
An ingenious design of a perovskite oxide heterostructure has been proposed for realizing antiferromagnetic spintronics in a two-dimensional conducting layer, assisted by anisotropic Rashba-Dresselhaus spin-orbit interaction. The present-day computer processors have long been stagnant to a few GHz clock speed. Fortunately, the emerging technologies based on antiferromagnetic spintronics promises a THz speed — the speed at which antiferromagnetic textures can be manipulated. Moreover, the antiferromagnetic textures do not require a bias to preserve its state, offering a non-volatile memory that can operate at an extremely high frequency. All these dramatic improvements come with a promise of much lower power requirement, making antiferromagnetic spintronics a prominent research direction. In a design based on insightful theoretical calculations combining density functional theory and analytical modeling, the authors propose a heterostructure of non-polar SrIrO3|SrTiO3 with a polar LaAlO3, generating a two-dimensional conducting system at the interface. The ultra-thin two-dimensional conducting layer of SrIrO3, sandwiched between SrTiO3 and LaAlO3, hosts canted antiferromagnetism and strong anisotropic Rashba-Dresselhaus spin-orbit interaction, promising for generating spin-orbit torque that is necessary for manipulating the spin textures. Thus, the proposed novel heterostructure hosts the essential ingredients for technologies based on antiferromagnetic spintronics. Further, a proximity-induced Rashba-like spin-orbit interaction in Ti-3d states may open new avenues for designing functional heterostructures.
Some of our sponsored projects are listed bellow:
|Designing oxide heterostructures for quantum technology through first principles calculations||14 Mar 2022 - 13 Mar 2025||₹ 31,02,264|
|Magnetism and spin-orbit interaction at complex oxide interfaces for technology: An ab initio investigation||12 Jan 2017 - 11 Jan 2020||₹ 47,25,600|
ToMP invites motivated and dedicated researchers and research students interested in theoretical condensed matter physics, density functional theory, Monte Carlo simulations, and computer programming, aspiring to work in the research areas including magnetism, spin-orbit interaction, two-dimensional materials, nanomaterials and heterostructures, topological materials, and machine learning for the positions listed below.
Interested to join ToMP for MS or iPhD project? Please contact Nirmal Ganguli.