Skip to Main content Skip to Navigation

Étude par Monte Carlo quantique de la transition γ-α du cérium

Abstract : The 4f electrons are strongly localized and their on-site Coulomb repulsion is large compared to bandwidth. Among all lanthanides, cerium is particularly fascinating, due to the strong hybridization with the 6s-6p-5d bands, all present at the Fermi level. The origin of the cerium volume collapse along the isostructural γ-α transition has been a puzzle since its discovery in 1927. Experimentally, pure cerium undergoes the γ-α transition always at finite temperature T. Recently, very accurate X-ray diffraction measurements undoubtedly confirmed the first-order Fm-3m isostructural character of the transition. The first-order line extrapolates to zero-T at negative pressures. The cerium γ-α phase transition is characterized by means of a many-body Jastrow-correlated wave function, which minimizes the variational energy of the first-principles scalar-relativistic Hamiltonian, and includes correlation effects in a non-perturbative way. Our variational ansatz reproduces the structural properties of the two phases, and proves that even at temperature T = 0 K the system undergoes a first order transition, with ab-initio parameters which are seamlessly connected to the ones measured by experiment at finite T. We show that the transition is related to a complex rearrangement of the electronic structure, with key role played by the localisation of t1u orbitals, which tunes the Coulomb repulsion, and the character of the chemical bond.
Complete list of metadata

Cited literature [168 references]  Display  Hide  Download
Contributor : ABES STAR :  Contact
Submitted on : Tuesday, February 9, 2016 - 2:02:06 PM
Last modification on : Thursday, July 7, 2022 - 3:08:44 AM
Long-term archiving on: : Saturday, November 12, 2016 - 3:01:43 PM


Version validated by the jury (STAR)


  • HAL Id : tel-01271610, version 1


Nicolas Devaux. Étude par Monte Carlo quantique de la transition γ-α du cérium. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie - Paris VI, 2015. Français. ⟨NNT : 2015PA066373⟩. ⟨tel-01271610⟩



Record views


Files downloads