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Related papers: Thermodynamics of spin crossover in ferropericlase…

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Ferropericlase (Fp), (Mg$_\mathrm{1-x}$Fe$_\mathrm{x}$)O, is the second most abundant phase in the Earths lower mantle. At relevant pressure-temperature conditions, iron in Fp undergoes a high spin (HS), S=2, to low spin (LS), S=0, state…

Geophysics · Physics 2020-10-28 Michel L. Marcondes , Fawei Zheng , Renata M. Wentzcovitch

Ferropericlase (fp), (Mg$_{1-x}$Fe$_x$)O, the second most abundant mineral in the Earth's lower mantle, is expected to be an essential component of super-Earths' mantles. Here we present an ab initio investigation of the structure and…

Geophysics · Physics 2022-05-04 Tianqi Wan , Yang Sun , Renata M. Wentzcovitch

In this work, we systematically study the electronic structure and stability of spin states of the [Fe-(tpy-ph)$_2$]$^{2+}$ molecule in both gas phase and on a Au(111) substrate using density functional theory +U (DFT+U) calculations. We…

Materials Science · Physics 2024-08-22 Naveen K. Dandu , Alex Taekyung Lee , Sergio Ulloa , Larry Curtiss , Saw Wai Hla , Anh T. Ngo

Using density functional theory plus Hubbard $U$ calculations, we show that the ground state of (Mg,Fe)(Si,Fe)O$_3$ perovskite, a major mineral phase in the Earth's lower mantle, has high-spin ferric iron ($S=5/2$) at both the dodecahedral…

Geophysics · Physics 2015-05-27 Han Hsu , Peter Blaha , Matteo Cococcioni , Renata M. Wentzcovitch

With local density approximation + Hubbard $U$ (LDA+$U$) calculations, we show that the ferromagnetic (FM) insulating state observed in tensile-strained LaCoO$_3$ epitaxial thin films is most likely a mixture of low-spin (LS) and high-spin…

Strongly Correlated Electrons · Physics 2022-05-20 Han Hsu , Peter Blaha , Renata M. Wentzcovitch

Using the LDA+$\textit{U}_\text{sc}$ method, we present calculations phase relations of iron monoxides involving five polytypes in multiple spin-state configurations. The Hubbard parameter $U$ is determined self-consistently simultaneously…

Materials Science · Physics 2020-06-11 Yang Sun , Matteo Cococcioni , Renata M. Wentzcovitch

Spin crossover of iron is of central importance in solid Earth geophysics. It impacts all physical properties of minerals that altogether constitute $\sim 95$ vol\% of the Earth's lower mantle: ferropericlase [(Mg,Fe)O] and Fe-bearing…

Strongly Correlated Electrons · Physics 2015-06-23 Han Hsu , Renata M. Wentzcovitch

The results of magnetic and spectral properties calculation for paramagnetic phase of ferropericlase (Fe$_{1/4}$Mg$_{3/4}$)O at ambient and high pressures are reported. Calculations were performed by combined Local Density Approximation +…

Materials Science · Physics 2014-11-21 N. A. Skorikov , A. O. Shorikov , S. L. Skornyakov , M. A. Korotin

The Hubbard model at temperatures above the N\'{e}el transition, despite being a paramagnet, can exhibit rich physics due to the interplay of Fermi surface, on-site interaction $U$ and thermal fluctuations. Nevertheless, the understanding…

Strongly Correlated Electrons · Physics 2025-01-23 Yu-Feng Song , Youjin Deng , Yuan-Yao He

High-pressure properties of MnPS$_3$ are investigated by using the hybrid functional, we report a spin-crossover pressure of 35 GPa consisting with experimental observation (30 GPa), less than half of existing report (63 GPa) using the…

Strongly Correlated Electrons · Physics 2021-05-12 Hanxing Zhang , Caoping Ni , Jie Zhang , Liangjian Zou , Zhi Zeng , Xianlong Wang

Structural, magnetic and electrical-transport properties of {\alpha}-LiFeO2, crystallizing in the rock salt structure with random distribution of Li and Fe ions, have been studied by synchrotron X-ray diffraction, 57Fe M\"ossbauer…

Strongly Correlated Electrons · Physics 2017-09-29 Samar Layek , Eran Greenberg , Weiming Xu , Gregory Kh. Rozenberg , Moshe P. Pasternak , Jean-Paul Itié , Dániel G. Merkel

Using configuration-state-constrained electronic structure calculations based on the generalized gradient approximation plus Hubbard U method, we sought the origin of the giant tetragonal ferroelectric distortion in the ambient phase of the…

Strongly Correlated Electrons · Physics 2011-05-25 Ting Jia , Hua Wu , Guoren Zhang , Xiaoli Zhang , Ying Guo , Zhi Zeng , Hai-Qing Lin

We present LDA+U calculations of high temperature elastic properties of bridgmanite with composition (Mg$_{(1-x)}$Fe$_{x}^{2+}$)SiO$_3$ for $0\le{x}\le0.125$. Results of elastic moduli and acoustic velocities for the Mg-end member (x=0)…

Materials Science · Physics 2015-06-24 Gaurav Shukla , Zhongqing Wu , Han Hsu , Andrea Floris , Matteo Cococcioni , Renata M. Wentzcovitch

We explore how the spiral spin(SP) state, a spin singlet known to accompany fully-polarized ferromagnetic (F) states in the Hubbard model, is related with the F state in the thermodynamic limit using the density matrix renormalization group…

Condensed Matter · Physics 2009-10-31 Ryotaro Arita , Hideo Aoki

Ferropericlase, (Mg,Fe)O, is the second-most abundant mineral of the Earth's lower mantle. With increasing pressure, the Fe ions in the material begin to collapse from a magnetic to non-magnetic spin state. We present a finite-temperature…

Materials Science · Physics 2015-06-23 Eero Holmstrom , Lars Stixrude

The accuracy of LDA + U total energies is tested by predicting the high pressure behavior of rocksalt-structured FeO, including metal-insulator and magnetic transitions, equation of state, and lattice strain, as functions of the Coulomb…

Strongly Correlated Electrons · Physics 2007-05-23 S. A. Gramsch , R. E. Cohen , S. Y. Savrasov

We predict a new mechanism of enhancement of ferromagnetic phase transition temperature $T_c$ in uniaxially stressed diluted magnetic semiconductors (DMS) of p-type. Our prediction is based on comparative studies of both Heisenberg…

Disordered Systems and Neural Networks · Physics 2009-11-10 Yu. G. Semenov , V. A. Stephanovich

The magnetic properties of iron-arsenides are investigated using the LSDA+U approach. In addition to one high moment state, we find that a positive U also produces two low moment states with m~0.4 $\mu_{B}$ and m~1.0 $\mu_{B}$. The…

Superconductivity · Physics 2011-05-30 Guo-Qiang Liu

High purity iron, which transforms into the hcp phase under pressure, has recently been reported to be superconducing in the pressure range 150-300 kBar [shim]. The electronic structure and the electron-phonon coupling ($\lambda_{ph}$) are…

Superconductivity · Physics 2015-06-24 T. Jarlborg

We solve the 3D periodic Anderson model via two impurity DMFT. We obtain the temperature v.s. hybridization phase diagram. In approaching the quantum critical point (QCP) both the Neel and lattice Kondo temperatures decrease and they do not…

Strongly Correlated Electrons · Physics 2007-05-23 Ping Sun , Gabriel Kotliar
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