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Key research themes
1. How can semiempirical DFTB methods be parametrized and extended to improve intermolecular interaction predictions?
This research area focuses on enhancing the density functional tight binding (DFTB) method's accuracy and transferability, particularly in describing intermolecular interactions, polarizability, and energetics involving charged and polar species. Given the minimal basis nature of DFTB, researchers investigate parametrizations that incorporate polarization corrections, extended basis effects, and dispersion terms to reconcile efficiency with quantitative accuracy in varied chemical environments.
Key finding: The paper introduces an augmentation to the DFTB3 method using chemical-potential equalization (CPE) to include auxiliary polarizable response density, along with empirical dispersion corrections (D3). This hybrid... Read more
Key finding: This work presents a sparse self-consistent field (SCF) algorithm leveraging local molecular orbitals for efficient linear algebra operations in DFTB. The parallel implementation effectively exploits modern symmetric... Read more
Key finding: This study leverages GPU acceleration for DFTB-based metadynamics to simulate free energy surfaces of complex biochemical molecules like remdesivir, which is inaccessible with full DFT metadynamics due to computational cost.... Read more
2. How can relativistic effects and spin-orbit coupling be incorporated efficiently in electronic structure calculations relevant for heavy-element systems?
This theme investigates methodologies to incorporate relativistic corrections, including spin-orbit coupling, into electronic structure methods like DFT and tight-binding models. Accurately treating heavy elements and spin-dependent interactions is crucial for predictive modeling of magnetic materials, spectroscopy, and topological phenomena. Research addresses theoretical formulations, algorithmic implementations, and software capable of handling relativistic four-component Hamiltonians and connecting them to practical computational chemistry applications.
Key finding: The ReSpect program package implements fully variational two- and four-component relativistic DFT methods that include spin-orbit coupling and relativistic corrections from the Dirac equation, enabling accurate simulations of... Read more
Key finding: Using the relativistic augmented-plane-wave (RAPW) method, this study calculates electronic band structures and the Fermi surface of terbium, highlighting the importance of relativistic effects in heavy rare-earth elements... Read more
Key finding: By combining 57Fe Mössbauer spectroscopy and DFT+GGA calculations, this research elucidates the electronic and magnetic states of Fe ions in Co2FeBO5, taking into account spin and local environment effects influenced by... Read more
3. How can parametrization and modeling methodologies be used to understand and predict phase boundaries, domain structures, and correlated phenomena in complex magnetic materials?
This theme encompasses the use of computational and phenomenological models, often supported by parametrized Hamiltonians or energy functionals, to study structural phase boundaries, morphotropic phase boundaries (MPB), domain microstructure, magnetostriction, and other correlated electronic/magnetic phenomena in complex materials. Research combines ab initio parametrization, phase-field modeling, and effective Hamiltonian approaches tailored to capture subtle energy competitions and symmetries that govern material responses at different scales and conditions.
Key finding: Through micromagnetic microelastic phase-field modeling informed by parametrized magnetocrystalline anisotropy, exchange, and elastic interactions, this study demonstrates coexistence of rhombohedral and tetragonal phases... Read more
Key finding: Combining density functional theory (DFT) calculations with transport and magnetization measurements, this work reveals the presence of six-fold degenerate bands protected by nonsymmorphic symmetry in PdSb2. The derived band... Read more
Key finding: This paper introduces a combined FLEX+DMFT method derived from a Luttinger-Ward functional that self-consistently incorporates local and nonlocal correlations to study the d-wave superconductivity phase diagram. The... Read more