Research Projects

Electron localization by the vertune of strong correlations at integer filling is known as Mott Transition. Whereas, in case of Multiferroics, ferroelectricity and magnetism coexist and are expected to be crossed coupled. The current proposal is focused on the investigation and design of Mott Multiferroic materials. The idea is to tune the electron localization and delocalization during Mott transition by the variables of a Multiferroic material i.e., polarization and/or magnetization. Finding a material with intrinsic Mott transition at the same time displaying multiferroic properties is channlaging. Here, design of Mott Multiferroic materials will be explored by invoking structural mode coupling. We will take the advantage of hybrid improper ferroelectricity to facilitate polarization in the vicinity of Mott transition and investigate how the variation of the polar mode will affect such transition. The transition metal oxides (TMOs) with ABO3 perovskite architecture of the form ABO3/A’BO3 superlattices (SL) and AA’BB’O6 double perovskites (DP) will be systematically investigated. The TMO-ABO3 building blocks consisting of d¹, d², d⁴ and d⁷ electronic configurations of 3d, 4d and 5d-B or B’ sites will be considered. The choice of B or B’ sites is to create a Mott Transition situation and to develop finite magnetization of the system, whereas, A/A’ cation ordering will facilitate the ferroelectricity. Our approach is to induce both ferroelectricity, magnetism and Mott Transition simultaneously by multi structural mode coupling i.e., by “multimode coupling". The first-principles calculations, molecular dynamics simulations, DMFT, Quantum Monte Carlo methods will be employed to understand the interconnection between Mott physics and Multiferroics. After designing such Mott Multiferroic materials within TMO-ABO3 oxide and derivatives, a feature space will then be constructed with structural information, phonon modes, band width and filling as derived from electronic structure calculations, Coulomb correlation parameter U, spatial fluctuation in electronic correlation via SPA etc. A causal machine learning model will be constructed to list important features and causation among the features in the contest of controlling of Mott transition via polarization and/or magnetization ordering (or anisotropy). Design principles will be outlined and a robust theory for “Mott Multiferroic” materials will be developed. Finally, we will investigate the effect of strain, pressure, temperature and chemical doping on selective Mott Multiferroic materials to examine the controllability of the variables i.,e., polarization, magnetization and metal to insulator transition of such materials.

Mott Transition, Multiferroics, Density Functional Theory, Static path approximation, Quantum Monte Carlo, Structural mode coupling