Advanced Materials and Devices
Theory Group
Our research is interdisciplinary. We use first principles and analytical theories to explore the interplay between structural, electronic, mechanical, optical, and thermoelectric properties of complex materials for fundamental science advances and device proposals.
Topological Materials
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Using first principles methods calculations, we seek to understand how non-trivial topology affects basic properties of materials. Our group performs electronic structure calculations as well as first principles simulations of the optical response and Hall conductivity properties of a variety of materials in 3D and at the nanoscale. Linking specific features from the band structure to the bulk optical response and the surface conductivity due to Fermi arcs in Weyl semimetals gives powerful means to distinguish between topologically trivial and nontrivial contributions. We also compute the Hall response from first principles in van der Waals materials to explore how stacking or making different heterostructures can be explored for creating various types of topological materials.
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Adv. Theory Simul. 3,1900247 (2020)
PR Materials 3, 064002 (2019)
PR Materials 2, 014003 (2018)
Thermoelectric materials
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The structure-property relations in thermoelectric materials fundamentally determine how to optimize their performance for effective energy conversion. In collaboration with experimentalists, we design thermoelectric materials with enhanced performance relying on compositions of earth abundant constituents that are environmentally safe. Electronic structure and transport models are utilized in our group for the discovery of novel classes of materials which have robust low thermal conductivities with lots of routs for optimization of the electronic transport. Analytical models allow us to learn about transport beyond the standard Boltzmann semiclassical theory, especially in the context of thermoelectric materials with nontrivial topology.
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PR Materials 5, 045401 (2021)
Phys. Rev. Research 2, 033086 (2020)
Dalton Trans. 49, 2273 (2020)
2D Materials
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2D materials and heterostructures are a fruitful ground for the discovery of new phenomena and interactions. In our group, we focus on van der Waals systems and heterostructures by utilizing extensive first principles simulations and analytical models to understand not only the nature of van der Waals interactions, but also how novel effects can be mediated by such dispersive forces. Exploring 2D dilute magnetic semiconductors at the interface of opto-spin-caloritronics is a direction of current interest. Nonlinear and anisotropic factors affecting van der Waals interactions is also of much interest..
APL 119, 250501 (2021)
Appl. Sci. 11, 293 (2021)
Mater. Horiz. 7, 1413 (2020) ​
Light-Matter Interactions​
The interaction of electromagnetic excitations with objects has received much attention recently due to its importance for quantum materials and their relevance for quantum communication. In our group, we develop analytical models and first principles methods to investigate how van der Waals and Casimir-like phenomena are affected by the materials properties of the interacting objects. Our work is instrumental in understanding how the interplay between topological properties, stacking of chemically inert layers, anisotropy, and dimensionality contribute to the fundamental nature of fluctuation induced interactions between various systems.
Comm. Materials (Nature) 1, 14 (2020)
Phys. Rev. B 101, 075418 (2020)
Nat. Comm. 8, 14699 (2017)
Devices
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Understanding the behavior of materials helps us improve existing and propose devices with new functionalities and applications. For example, we seek to improve the operation of standard thermoelectric modules operating in power generation or cooling modes by optimizing the materials used for their construction. In addition, we propose the design of thermoelectric cloaks or thermoelectric concentrators which can operate under very general conditions. We also design devices capable of separating thermoelectrically coupled heat and electric flows further expanding the application of thermoelectric materials.
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J. Phys.: Energy 4, 014001 (2022)
J. Appl. Phys. 128, 025104 (2020)
J. Phys.: Energy 1, 025002 (2019)