Magnetism and spin-based functionalities are crucial for energy-efficient, faster, and smaller electronics. My research focuses on studying and predicting new magnetic materials and spin-based functionalities for spintronic applications. We aim to understand and develop mechanisms of magnetization reversal with ultra-low current and applied electric fields. Simulating novel magnetization reversal processes under finite fields remains challenging. Our research involves: 1. Studying effective models to investigate magnetization reversal processes and dynamics of ferroelectric/magnetoelectric/magnetoelastic domains under external fields, 2. Harnessing defect engineering to design novel magnetization reversal processes through strategic design. 3. Utilizing data-driven methods based on machine learning to screen materials for desirable performances.

Selected Pubmications:

# Hunnestad, Das et al., Nat. Commun. 15, 5400 (2024)

# Das, Phys. Rev. Research 5, 013007 (2023)

# Lee, Das et al., Phys. Rev. Materials 6, 064401 (2022)

# Shaikh, Das et al., Chem. Mater. 33, 1594-1606 (2021)

# Fan, Das et al., Nat. Commun. 11, 5582 (2020)

# Mundy, Das et al., Nature 537, 523 (2016)

# Das et al., Nat. Commun. 5, 2998 (2014)

# Geng, Das et al., Nat. Mater. 13, 163-167 (2014)

The formation of spontaneous orders of magnetic moments (like collinear ferromagnetic (FM), antiferromagnetic (AMF) orders, non-collinear orders and non-trivial topological spin structures) or cooperative quantum phase with fluctuating spins down to lowest temperature (like quantum spin liquids) in a material, is driven by various quantum mechanical exchange interactions between the constituent magnetic ions and their mutual interplay. Understanding this complex interplay at the level of atoms and electrons, which leads to the emergence of unique magnetic phenomena, is one of the major objectives of my endeavors.

The combination of proximity to the Mott transition and strong spin-orbit coupling (SOC) is common in 4d/5d transition metal (TM) compounds. We are interested in exploring the emergence of novel quantum states, phase transitions, and multi-functional phenomena arising from the interplay between SOC and electronic correlations in various TM compounds.

Selected Pubmications:

# Das et al., Phys. Rev. Materials 5, 124416 (2021)

# Ye, Zhao, Das et al., Nat. Commun. 12, 1917 (2021)

# Takiguchi, Wakabayashi, Das et al., Nat. Commun. 11, 4969 (2020)

# Valli, Das et al., Phys. Rev. B 92, 115143 (2015)

# Das et al., Phys. Rev. Lett. 107, 197202 (2011)

# Das et al., Phys. Rev. B 83, 104418 (2011)

# Das et al., Phys. Rev. B 77, 224437 (2008) (Editor's choice)

# Das et al., Phys. Rev. Lett. 100, 186402 (2008)

My focus on understanding and simulating the temperature and field dependence of crystal structures and phase transitions and properties of functional materials. We develop and utilize ab initio computational methods to establish the efficacy of ab initio techniques in capturing the "Structure-Property" duality at finite temperatures and fields, which is currently in its early stages of development. Additionally, these methods will bridge the gap between theoretical predictions and experimental realization.

Thermal expansion is a fundamental physical property of condensed matter. In device applications even a weak thermal expansion can lead to the development of thermal stresses which can ultimately lead to device failure. We are interested in the understanding and modelling of the mechanisms of thermal expansion by combining various ab initio techniques. We employ a combined approach of the anharmonic potential cluster expansion (APCE) and Ab initio molecular dynamics to study thermal expansion properties of strongly anharmonic systems.

Selected Pubmications:

# Koike, Das et al., Solids 5(3), 422-433 (2024)

# Liu, Das et al., Chem. Mater. 36, 1899-1907 (2024)

# Hu, Das et al., Chem. Mater. 33, 7665-7674 (2021)

# Ohashi, Das et al., Chem. Mater. 32, 9753-9760 (2020)

# Sakai, Das et al., Chem. Mater. 31, 4748-4758 (2019)

# Das et al., Chem. Mater. 29, 7840-7851 (2017)