2026/06/08 by Yao Wei, Siyu Chen, Evgeny Plekhanov +4 · 1 voice
Materials Science · Physics and Astronomy · #Field (mathematics) #Machine Learning in Materials Science #Phonon #Rare-earth and actinide compounds #Renormalization #State (computer science) #Thermal Expansion and Ionic Conductivity #Work (physics)
paper · pdf · doi:10.1103/zm4r-vs8j
openalex publication_date 2026/06/23 · openalex created_date 2026/06/24 · openalex updated_date 2026/08/05
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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mi>f</a:mi> </a:math> -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 <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:mrow> <b:mi>DFT</b:mi> <b:mo>+</b:mo> <b:mi>DMFT</b:mi> </b:mrow> </b:math> levels, subsequently incorporating the vibrational free energy derived from the phonon density of states. Our findings reveal that electronic renormalization of the force constants significantly alters the phonon spectra, particularly in the strongly correlated <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mi>γ</c:mi> </c:math> 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 with experiment, finding significantly closer agreement than conventional DFT and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:mrow> <d:mi>DFT</d:mi> <d:mo>+</d:mo> <d:mi mathvariant="normal">U</d:mi> </d:mrow> </d:math> 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.