A unified and efficient theory for the structural properties of actinides and phases of plutonium

We show that a calculation using density functional theory (DFT) in the generalized gradient approximation (GGA) supplemented by an explicit Coulomb interaction term between correlated electrons (GGA+U), can accurately describe structural properties of (1) the room temperature phases of U, Np, Pu, Am and Cm, and (2) the α, β, γ, δ and ϵ phases of plutonium, as does the combination of GGA with dynamical mean field theory (DMFT). It thus changes the view on the role of electronic interaction in these systems and opens the way to fast calculations of structural properties in actinides metallic system. We use ab initio values of effective Coulomb interactions and underline that Hund's exchange and spin-orbit coupling are of utmost importance in these calculations. Secondly, we show that phonons properties in δ plutonium are impacted by strong interactions. The GGA+DMFT results exhibits a lattice instability for the transverse (1 1 1) phonon mode. Moreover the amplitude of this lattice instability is consistent with the experimental temperature of stability of this phase. Our calculation thus shows that when the δ phase is thermodynamically unstable (at 0 K), it is also dynamically unstable.

[1]  K. Ho,et al.  Phase Diagram and Electronic Structure of Praseodymium and Plutonium , 2015 .

[2]  A. Kutepov,et al.  First-principles study of electronic and magnetic structure of alpha-Pu, delta-Pu, americium, and curium , 2004 .

[3]  G. Kotliar,et al.  Site-selective electronic correlation in α-plutonium metal , 2013, Nature Communications.

[4]  François Bottin,et al.  Phonon spectra of plutonium at high temperatures , 2017 .

[5]  E. Bauer,et al.  The valence-fluctuating ground state of plutonium , 2015, Science Advances.

[6]  J. Wills,et al.  Spectral properties of δ -plutonium: Sensitivity to 5f occupancy , 2007, 0705.1354.

[7]  R. Xu,et al.  Phonon Dispersions of fcc δ-Plutonium-Gallium by Inelastic X-ray Scattering , 2003, Science.

[8]  Electronic structure of Pu and Am metals by self-consistent relativistic GWmethod , 2011, 1112.0214.

[9]  W. Zachariasen,et al.  The crystal structure of alpha plutonium metal , 1963 .

[10]  G. Kotliar,et al.  What is the valence of a correlated solid? The double life of delta-plutonium , 2006, cond-mat/0611760.

[11]  Silke Biermann,et al.  Towards a First-Principles Determination of Effective Coulomb Interactions in Correlated Electron Materials: Role of Intershell Interactions. , 2015, Physical review letters.

[12]  Fang Liu,et al.  Recent developments in the ABINIT software package , 2016, Comput. Phys. Commun..

[13]  Many-body electronic structure of americium metal. , 2005, Physical review letters.

[14]  J. E. Klepeis,et al.  Phonon and magnetic structure in δ-plutonium from density-functional theory , 2015, Scientific Reports.

[15]  A. Pasturel,et al.  Calculated thermodynamic properties of plutonium metal , 2003 .

[16]  C. Marianetti,et al.  Electronic coherence in δ-Pu: A dynamical mean-field theory study , 2008 .

[17]  J. Bouchet,et al.  Refinement of the equation of state ofα-uranium , 2013 .

[18]  B. Amadon.  Erratum: First-principles DFT+DMFT calculations of structural properties of actinides: Role of Hund's exchange, spin-orbit coupling, and crystal structure [Phys. Rev. B 94, 115148 (2016)] , 2018 .

[19]  D Vollhardt,et al.  First-principles calculation of atomic forces and structural distortions in strongly correlated materials. , 2014, Physical review letters.

[20]  G. Lander,et al.  Absence of Magnetic Moments in Plutonium , 2004, cond-mat/0410634.

[21]  Markus Aichhorn,et al.  Reduced effective spin-orbital degeneracy and spin-orbital ordering in paramagnetic transition-metal oxides: Sr2IrO4 versus Sr2RhO4. , 2011, Physical review letters.

[22]  A. Pasturel,et al.  Equilibrium properties of δ-Pu : LDA + U calculations (LDA ≡ local density approximation) , 2000 .

[23]  O. Gunnarsson,et al.  Density-functional calculation of effective Coulomb interactions in metals. , 1991, Physical review. B, Condensed matter.

[24]  V. Drchal,et al.  Multiplet effects in the electronic structure of δ-Pu, Am and their compounds , 2006, cond-mat/0610794.

[25]  Yi Wang,et al.  First-principles thermodynamic calculations for δ-Pu and ε-Pu , 2000 .

[26]  G. Kotliar,et al.  Correlated electrons in δ-plutonium within a dynamical mean-field picture , 2001, Nature.

[27]  Andrew J. Millis,et al.  Spin-density functional theories and their +U and +J extensions: A comparative study of transition metals and transition metal oxides , 2016 .

[28]  J. R. Peterson,et al.  X-ray diffraction of curium-248 metal under pressures of up to 52 GPa , 1985 .

[29]  J. Betts,et al.  Zero-temperature bulk modulus of alpha-plutonium , 2005 .

[30]  Hiroki Nakamura,et al.  Effects of spin-orbit coupling and strong correlation on the paramagnetic insulating state in plutonium dioxides , 2010 .

[31]  K. Litfin,et al.  Pressure induces major changes in the nature of Americium's 5f electrons. , 2000, Physical review letters.

[32]  C. Marianetti,et al.  Electronic structure calculations with dynamical mean-field theory , 2005, cond-mat/0511085.

[33]  B. Sadigh,et al.  Pressure-induced changes in the electronic structure of americium metal , 2011 .

[34]  B. Sadigh,et al.  Density-functional calculations of α, β, γ, δ, δ', and ε plutonium , 2004 .

[35]  D. Wallace.  Electronic and phonon properties of six crystalline phases of Pu metal , 1998 .

[36]  J. R. Peterson,et al.  The magnetic susceptibility of 248Cm metal , 1980 .

[37]  P. Söderlind.  First-principles phase stability, bonding, and electronic structure of actinide metals , 2014 .

[38]  Bernard Amadon,et al.  First-principles DFT+DMFT calculations of structural properties of actinides: Role of Hund's exchange, spin-orbit coupling, and crystal structure , 2016 .

[39]  Matthias Troyer,et al.  Continuous-time solver for quantum impurity models. , 2005, Physical review letters.

[40]  Xavier Gonze,et al.  Implementation of the projector augmented-wave method in the ABINIT code: Application to the study of iron under pressure , 2008 .

[41]  Kristjan Haule,et al.  Forces for structural optimizations in correlated materials within a DFT+embedded DMFT functional approach , 2016, 1602.02819.

[42]  J. Kress,et al.  Mott Transition in a Metallic Liquid: Gutzwiller Molecular Dynamics Simulations. , 2015, Physical review letters.

[43]  P. Faure,et al.  X-ray diffraction study of pure plutonium under pressure , 2009 .

[44]  A. I. Lichtenstein,et al.  Frequency-dependent local interactions and low-energy effective models from electronic structure calculations , 2004 .

[45]  G. Kotliar,et al.  Computational modeling of actinide materials and complexes , 2010 .

[46]  Nature of the 5f states in actinide metals , 2008, 0807.0416.

[47]  J. Betts,et al.  Temperature dependence of elastic moduli of polycrystalline β plutonium , 2011 .

[48]  M. Torrent,et al.  Influence of point defects and impurities on the dynamical stability of δ-plutonium , 2017, Journal of physics. Condensed matter : an Institute of Physics journal.

[49]  B. Sadigh,et al.  Density-functional calculations of alpha, beta, gamma, delta, delta', and epsilon plutonium. , 2004, Physical review letters.

[50]  P. Söderlind,et al.  {\it Ab initio} equation-of-state and elastic properties of Pu metal and Pu-Ga alloys , 2010 .

[51]  Antoine Georges,et al.  Plane-wave based electronic structure calculations for correlated materials using dynamical mean-field theory and projected local orbitals , 2008, 0801.4353.

[52]  R. Ahuja,et al.  A High-Pressure Structure in Curium Linked to Magnetism , 2005, Science.

[53]  F. Jollet,et al.  γandβcerium:LDA+Ucalculations of ground-state parameters , 2008 .

[54]  M. Katsnelson,et al.  Importance of full Coulomb interactions for understanding the electronic structure of delta-Pu , 2010 .

[55]  G. Kotliar,et al.  Calculated Phonon Spectra of Plutonium at High Temperatures , 2003, Science.

[56]  Jordan Bieder,et al.  Thermodynamics of the α-γ transition in cerium from first principles , 2013, 1305.7481.

[57]  Alexis Gerossier,et al.  Comparative analysis of models for the α − γ phase transition in cerium: A DFT+DMFT study using Wannier orbitals , 2015 .

[58]  W. Krauth,et al.  Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions , 1996 .