Atomic Scale Modeling of Alloys and Functional Materials
Title: Atomic Scale Modeling of Alloys and Functional Materials
SNIC Project: SNIC 2020/5-586
Project Type: SNIC Medium Compute
Principal Investigator: Paul Erhart <>
Affiliation: Chalmers tekniska högskola
Duration: 2020-12-01 – 2021-12-01
Classification: 10304


# Thermodynamic and optical properties of metallic nanostructures Metallic nanostructures are of interest for many areas, including, e.g., catalysis, medicine, energy conversion and storage. The properties of these particles are very sensitive to variations in size, shape, composition and adsorbates, which provides exciting opportunities for engineering materials properties all the way from the electronic to the mesoscale. Studies of the thermodynamic and optical properties of these structures are a core topic in our research group. The main computational tools in this context are density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations along with empirical potentials in connection wtih molecular dynamics and Monte Carlo simulations. We are also increasingly integrating electrodynamic simulations using the finite-difference time-domain (FDTD) approach in our workflows. In the coming years we will continue our research in this area targeting in particular multi-component ("nanoalloy") systems and strong light-matter coupling. Here, we will study, e.g., the optimization of alloyed nanostructures for sensing and catalysis in the space spanned by composition, shape and size, employing a bottom-up approach that combines DFT, TDDFT and FDTD calculations with Bayesian optimization based on Gaussian processes. We will also investigate hybrid light-matter systems comprising molecules, nanoparticles and cavities, both via full TDDFT calculations and using hybrid approaches for scaling up system size and complexity. # Impact of defects on transport and optical properties Understanding and manipulating the impact of defects on the transport and optical properties of materials is of interest to a large number of applications, including electronic and optoelectronic devices, thermal management, thermoelectric energy generation and materials for quantum computing. This motivates our research interest in the electronic and atomic scale description of defect and transport properties and many ongoing collaborating with groups in Sweden, Finland, Germany, Austria and the United States. Materials of interest include both 2D materials such as transition metal dichalcogenides (thermal transport, exciton dynamics) or hexagonal boron nitride (single-photon emitters) and bulk materials such as clathrates (thermal and electrical transport, ordering phenomena), zeolites (catalytic properties), silicon carbide (single-photon emitters) and phosphors (solid-state lighting). In this research are, we use both first-principles calculations based on DFT and semi-empirical models in combination with solvers for the Boltzmann transport equation as well as molecular dynamics simulations for thermal conductivity simulations in the classical limit. To deal with the large number of degrees of freedom and the chemical complexity of these systems we are continuously developing our methods and software packages. In the coming years we will continue our research on two-dimensional materials and increase our effort on single-photon emitters. The excitations supported by the latter can be coupled to other optical excitations, including plasmons and excitons, creating an exciting bridge between our research on defects, metallic nanostructures and strong coupling. In addition, we will apply our methodology to new systems, specifically mixed halide perovskites with the goal of resolving thermodynamic and electronic properties of in these chemically and electronically complex materials.