Correlation-driven phonon renormalisation and the equation of state of $\gamma$-cerium

Abstract

We investigate the thermodynamic properties of elemental cerium by assessing the crucial role of phonon free energy within the framework of dynamical mean-field theory (DMFT). While conventional density functional theory (DFT) often fails to capture the intricate energy landscape of $f$-electron materials, our approach integrates many-body electronic correlations with lattice dynamics to achieve a more rigorous description of the equation of state. We calculate the total energy as a function of the lattice constant at both the DFT and DFT+DMFT levels, subsequently incorporating the vibrational free energy derived from the phonon density of states. Our findings reveal that electronic renormalisation of the force constants significantly alters the phonon spectra, particularly in the strongly correlated $\gamma$-phase. By applying these phonon corrections to the energy profiles, we observe a substantial refinement in the predicted equilibrium volumes. Using principal-component-based machine learning, we interpolate phonon dispersions continuously from a finite set of first-principles calculations and compare them to experiment, finding significantly closer agreement compared to conventional DFT and DFT+U calculations that neglect dynamical many-body correlations. This study underlines the necessity of accounting for both electronic and vibrational entropy when evaluating the phase stability and structural transitions of lanthanide systems under varying pressures and temperatures.

arXiv comment12 pages, 6 figures

References in corpus (30)

• Continuous-time Monte Carlo methods for quantum impurity models
• Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base
• Dynamical Mean-Field Theory within the Full-Potential Methods: Electronic structure of Ce-115 materials
• First principles approach to the electronic structure of strongly correlated systems: combining GW and DMFT
• Exact double-counting in combining the Dynamical Mean Field Theory and the Density Functional Theory
• The Cerium volume collapse: Results from the LDA+DMFT approach
• Self-consistency over the charge-density in dynamical mean-field theory: a linear muffin-tin implementation and some physical implications
• Lattice dynamics and electron-phonon coupling calculations using non-diagonal supercells
• The alpha-gamma transition of Cerium is entropy-driven
• Free energy from stationary implementation of the DFT+DMFT functional
• The alpha to gamma transition in Ce: a theoretical view from optical spectroscopy
• Thermodynamic and spectral properties of compressed Ce calculated by the merger of the local density approximation and dynamical mean field theory
• Calculated phonon spectra of paramagnetic iron at the alpha-gamma phase transition
• The role of the lattice in the $\gamma \to \alpha$ phase transition of Ce: a high pressure neutron and x-ray diffraction study
• The $\gamma$-$\alpha$ iso-structural Transition in Cerium, a Critical Element
• Forces for Structural Optimizations in Correlated Materials within DFT+Embedded DMFT Functional Approach
• Thermoelectricity in correlated narrow-gap semiconductors
• A Self-consistent DFT+DMFT scheme in the Projector Augmented Wave : Applications to Cerium, Ce2O3 and Pu2O3 with the Hubbard I solver and comparison to DFT+U
• Density-functional Theory for f electron Systems: the α-γ Phase Transition in Cerium
• Electronic correlations determine the phase stability of iron up to the melting temperature
• Merging GW with DMFT and non-local correlations beyond
• Thermodynamics of the α-γ transition in Cerium from first principles
• Electronic structure of cerium: A comprehensive first-principles study
• First-principles Calculation of Atomic Forces and Structural Distortions in Strongly Correlated Materials
• Efficient lattice dynamics calculations for correlated materials with DFT+DMFT
• $\alpha -\gamma$ transition in cerium: magnetic form factor and dynamic magnetic susceptibility in dynamical mean-field theory
• The phonon softening due to melting of the ferromagnetic order in elemental iron
• Many-body renormalisation of forces in f-electron materials
• Correlation Driven Phonon Anomalies in Bulk FeSe
• Impact of electronic correlations on the superconductivity of high-pressure CeH${}_9$