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Mosquera-Lois I, Kavanagh SR, Klarbring J, Tolborg K, Walsh A. Imperfections are not 0 K: free energy of point defects in crystals. Chem Soc Rev 2023; 52:5812-5826. [PMID: 37565783 DOI: 10.1039/d3cs00432e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Defects determine many important properties and applications of materials, ranging from doping in semiconductors, to conductivity in mixed ionic-electronic conductors used in batteries, to active sites in catalysts. The theoretical description of defect formation in crystals has evolved substantially over the past century. Advances in supercomputing hardware, and the integration of new computational techniques such as machine learning, provide an opportunity to model longer length and time-scales than previously possible. In this Tutorial Review, we cover the description of free energies for defect formation at finite temperatures, including configurational (structural, electronic, spin) and vibrational terms. We discuss challenges in accounting for metastable defect configurations, progress such as machine learning force fields and thermodynamic integration to directly access entropic contributions, and bottlenecks in going beyond the dilute limit of defect formation. Such developments are necessary to support a new era of accurate defect predictions in computational materials chemistry.
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Affiliation(s)
- Irea Mosquera-Lois
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
| | - Seán R Kavanagh
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- Thomas Young Centre & Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - Johan Klarbring
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83, Linköping, Sweden
| | - Kasper Tolborg
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- I-X, Imperial College London, London W12 0BZ, UK
| | - Aron Walsh
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- Department of Physics, Ewha Womans University, Seoul 03760, Korea
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2
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Jung SK, Gwon H, Kim H, Yoon G, Shin D, Hong J, Jung C, Kim JS. Unlocking the hidden chemical space in cubic-phase garnet solid electrolyte for efficient quasi-all-solid-state lithium batteries. Nat Commun 2022; 13:7638. [PMID: 36496481 PMCID: PMC9741625 DOI: 10.1038/s41467-022-35287-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022] Open
Abstract
Garnet-type Li7La3Zr2O12 (LLZO) solid electrolytes (SE) demonstrates appealing ionic conductivity properties for all-solid-state lithium metal battery applications. However, LLZO (electro)chemical stability in contact with the lithium metal electrode is not satisfactory for developing practical batteries. To circumvent this issue, we report the preparation of various doped cubic-phase LLZO SEs without vacancy formation (i.e., Li = 7.0 such as Li7La3Zr0.5Hf0.5Sc0.5Nb0.5O12 and Li7La3Zr0.4Hf0.4Sn0.4Sc0.4Ta0.4O12). The entropy-driven synthetic approach allows access to hidden chemical space in cubic-phase garnet and enables lower solid-state synthesis temperature as the cubic-phase nucleation decreases from 750 to 400 °C. We demonstrate that the SEs with Li = 7.0 show better reduction stability against lithium metal compared to SE with low lithium contents and identical atomic species (i.e., Li = 6.6 such as Li6.6La3Zr0.4Hf0.4Sn0.4Sc0.2Ta0.6O12). Moreover, when a Li7La3Zr0.4Hf0.4Sn0.4Sc0.4Ta0.4O12 pellet is tested at 60 °C in coin cell configuration with a Li metal negative electrode, a LiNi1/3Co1/3Mn1/3O2-based positive electrode and an ionic liquid-based electrolyte at the cathode|SE interface, discharge capacity retention of about 92% is delivered after 700 cycles at 0.8 mA/cm2 and 60 °C.
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Affiliation(s)
- Sung-Kyun Jung
- grid.419666.a0000 0001 1945 5898Battery Material Lab, Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678 Republic of Korea ,grid.42687.3f0000 0004 0381 814XSchool of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST‐gil, Ulsan, 44919 Republic of Korea
| | - Hyeokjo Gwon
- grid.419666.a0000 0001 1945 5898Battery Material Lab, Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678 Republic of Korea
| | - Hyungsub Kim
- grid.418964.60000 0001 0742 3338Neutron Science Center, Korea Atomic Energy Research Institute (KAERI), 111 Daedeok‐daero 989 Beon‐Gil, Yuseong‐gu, Daejeon 34057 Republic of Korea
| | - Gabin Yoon
- grid.419666.a0000 0001 1945 5898Battery Material Lab, Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678 Republic of Korea
| | - Dongki Shin
- grid.35541.360000000121053345Energy Materials Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Jihyun Hong
- grid.35541.360000000121053345Energy Materials Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Changhoon Jung
- grid.419666.a0000 0001 1945 5898Analytical Engineering Group, Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678 Republic of Korea
| | - Ju-Sik Kim
- grid.419666.a0000 0001 1945 5898Battery Material Lab, Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678 Republic of Korea
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Liang X, Hou TP, Zhang D, Luo WD, Cheng S, Zheng YH, Wu KM. New evaluation of the thermodynamics stability for bcc-Fe. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:455801. [PMID: 36007519 DOI: 10.1088/1361-648x/ac8cc6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
The thermodynamic properties for bcc-Fe were predicted by combination of the first-principles calculations, the quasiharmonic approximation, the CALPHAD method and the Weiss molecular field theory. The hybrid method considers the effects of the lattice vibration, electron, intrinsic magnetism and external magnetic fields on the thermodynamic properties at finite temperature. Combined with experimental data, the calculated heat capacity without external magnetic fields was used to verify the validity of the hybrid method. Close to the Fermi level the high electronic density of states leads to a significant electronic contribution to free energy. Near the Curie temperature lattice vibrations dominant the Gibbs free energy. The order of the other three excitation contributions to Gibbs free energy from high to low is: intrinsic magnetism > electron > external magnetic fields. The investigation suggests that all the excitation contributions to Gibbs free energy are not negligible which provides a correct direction for tuning the thermodynamic properties for Fe-based alloy.
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Affiliation(s)
- X Liang
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - T P Hou
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - D Zhang
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - W D Luo
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - S Cheng
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - Y H Zheng
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - K M Wu
- The State Key Laboratory for Refractories and Metallurgy, International Research Institute for Steel Technology, Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
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Mu Y, Wang BT, Li SD, Ding F. A family of superconducting boron crystals made of stacked bilayer borophenes. NANOSCALE 2022; 14:9754-9761. [PMID: 35766045 DOI: 10.1039/d2nr02013k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Monolayer borophenes tend to be easily oxidized, while thicker borophenes have stronger antioxidation properties. Herein, we proposed four novel metallic boron crystals by stacking the experimentally synthesized borophenes, and one of the crystals has been reported in our previous experiments. Bilayer units tend to act as blocks for crystals as determined by bonding analyses. Their kinetic, thermodynamic and mechanical stabilities are confirmed by our calculated phonon spectra, molecular dynamics and elastic constants. Our proposed allotropes are more stable than the boron α-Ga phase below 1000 K at ambient pressure. Some of them become more stable than the α-rh or γ-B28 phases at appropriate external pressure. More importantly, our calculations show that three of the proposed crystals are phonon-mediated superconductors with critical temperatures of about 5-10 K, higher than those of most superconducting elemental solids, in contrast to typical boron crystals with significant band gaps. Our study indicates a novel preparation method for metallic and superconducting boron crystals dispensing with high pressure.
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Affiliation(s)
- Yuewen Mu
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
| | - Bao-Tian Wang
- Spallation Neutron Source Science Center, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Dongguan, Guangdong 523803, China
| | - Si-Dian Li
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
| | - Feng Ding
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, South Korea.
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Holm A, Schmalfuß J, Mayr SG. Exploring Coupled Martensitic and Order–Disorder Phase Transitions in Fe
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Shape Memory Alloys Equilibrated Along the Bain Path: An Embedded Atom Method and Ab Initio Based Monte Carlo Study. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202100372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Alexander Holm
- Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig Germany
- Division of Surface Physics, Department of Physics and Earth Sciences University of Leipzig Linnestr. 5 04103 Leipzig Germany
| | - Jonathan Schmalfuß
- Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig Germany
| | - Stefan G. Mayr
- Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig Germany
- Division of Surface Physics, Department of Physics and Earth Sciences University of Leipzig Linnestr. 5 04103 Leipzig Germany
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Zhang J, Dong H, Li X, Wang Z, Xiao D. Temperature-driven phase transition of Ti2CN from first-principles calculations. Phys Chem Chem Phys 2022; 24:20848-20855. [DOI: 10.1039/d2cp01466a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First-principles evolutionary simulations are used to predict the stable compound of Ti2CN. Body-centered tetragonal I41/amd-Ti2CN is found to be more energetically favorable than other Ti2CN compounds at 0 K. The...
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Eisenbach M, Pei Z, Liu X. First-principles study of order-disorder transitions in multicomponent solid-solution alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:273002. [PMID: 30917351 DOI: 10.1088/1361-648x/ab13d8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this review, we will focus on the recent development of the order-disorder transition in metallic materials. The past decades have witnessed fast development in the first-principles methodologies and their applications to ordering transitions in multi-component alloys, particularly the high-entropy alloys. The driving force for the proceedings comes from (i) the advance of algorithms and increasingly cheaper hardware, and also (ii) the great passion to model alloys with increasing number of components. The review starts with a brief introduction of the history for the ordering transitions. More detailed scientific proceedings prior to the 1970s had been well summarized in Krivoglaz and Smirnov (1965 The Theory of Order-Disorder in Alloys (New York: Elsevier)) and Stoloff and Davies (1968 Prog. Mater. Sci. 13 1-84). In the second part, the methods to study the ordering transitions, primarily on the theoretic methods are introduced. These will include (i) KKR-CPA method and supercell methods for energetic calculations; and (ii) thermodynamic and statistical methods to compute the transition temperatures. The third part will focus on representative applications in alloys, including our own work and many others. This part supplies the primary information of this review to the readers. The fourth part will summarize the connections between ordering transitions and broader physical properties (e.g. the mechanical properties). In the last part, some concluding remarks and perspectives will be given.
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Affiliation(s)
- Markus Eisenbach
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
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Guo S, Yang K, Zeng Z, Zhang Y. Influence of defect distribution on the thermoelectric properties of FeNbSb based materials. Phys Chem Chem Phys 2018; 20:14441-14449. [DOI: 10.1039/c8cp02071j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cooperative effects of a solid solution and phase separation could strongly scatter phonons and improve the performance of thermoelectric materials.
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Affiliation(s)
- Shuping Guo
- Key Laboratory of Materials Physics
- Institute of Solid State Physics
- Chinese Academy of Sciences
- Hefei 230031
- China
| | - Kaishuai Yang
- Key Laboratory of Materials Physics
- Institute of Solid State Physics
- Chinese Academy of Sciences
- Hefei 230031
- China
| | - Zhi Zeng
- Key Laboratory of Materials Physics
- Institute of Solid State Physics
- Chinese Academy of Sciences
- Hefei 230031
- China
| | - Yongsheng Zhang
- Key Laboratory of Materials Physics
- Institute of Solid State Physics
- Chinese Academy of Sciences
- Hefei 230031
- China
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Tan TL, Jin HM, Sullivan MB, Anasori B, Gogotsi Y. High-Throughput Survey of Ordering Configurations in MXene Alloys Across Compositions and Temperatures. ACS NANO 2017; 11:4407-4418. [PMID: 28297600 DOI: 10.1021/acsnano.6b08227] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
2D transition metal carbides and nitrides known as MXenes are gaining increasing attention. About 20 of them have been synthesized (more predicted) and their applications in fields ranging from energy storage and electromagnetic shielding to medicine are being explored. To facilitate the search for double-transition-metal MXenes, we explore the structure-stability relationship for 8 MXene alloy systems, namely, (V1-xMox)3C2, (Nb1-xMox)3C2, (Ta1-xMox)3C2, (Ti1-xMox)3C2, (Ti1-xNbx)3C2, (Ti1-xTax)3C2, (Ti1-xVx)3C2, and (Nb1-xVx)3C2, with 0 ≤ x ≤ 1, using high-throughput computations. Starting from density-functional theory calculated formation energies, we used the cluster expansion method to build quick-to-compute interactions, enabling us to scan through the formation energies of millions of alloying configurations. For the Mo-rich MXenes, (M11-xMox)3C2 (where M1: Ti, V, Nb, Ta) Mo atoms prefer to occupy the surface layers, and ordering persists to high temperatures, based on our Monte Carlo simulations. When Ti is alloyed with Nb or Ta, in the Ti-rich MXenes, Ti atoms prefer the surface layers (e.g., Ti-C-Nb-C-Ti sequence), and in the Nb- or Ta-rich MXenes, Ti occupies only one surface layer and the other two layers are Nb or Ta (e.g., Ti-C-Nb-C-Nb), exhibiting asymmetric ordering. However, alloying Ti with V results in solid solutions across all compositions. (Nb1-xVx)3C2 phase separates at lower temperatures but forms solid solutions at synthesis temperatures. Postsynthesis annealing at moderate temperatures (800 to 1000 K) increases the ordering for all the compositions. Lastly, by investigating the stability of their precursor MAX phases and surface-terminated MXenes, we discuss the synthesis possibilities of highly ordered MXenes.
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Affiliation(s)
- Teck Leong Tan
- Institute of High Performance Computing, Agency for Science, Technology and Research , 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Hong Mei Jin
- Institute of High Performance Computing, Agency for Science, Technology and Research , 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Michael B Sullivan
- Institute of High Performance Computing, Agency for Science, Technology and Research , 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Babak Anasori
- A.J. Drexel Nanomaterials Institute, and Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Yury Gogotsi
- A.J. Drexel Nanomaterials Institute, and Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
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Rogal L, Bobrowski P, Körmann F, Divinski S, Stein F, Grabowski B. Computationally-driven engineering of sublattice ordering in a hexagonal AlHfScTiZr high entropy alloy. Sci Rep 2017; 7:2209. [PMID: 28526830 PMCID: PMC5438366 DOI: 10.1038/s41598-017-02385-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 04/11/2017] [Indexed: 11/24/2022] Open
Abstract
Multi-principle element alloys have enormous potential, but their exploration suffers from the tremendously large range of configurations. In the last decade such alloys have been designed with a focus on random solid solutions. Here we apply an experimentally verified, combined thermodynamic and first-principles design strategy to reverse the traditional approach and to generate a new type of hcp Al-Hf-Sc-Ti-Zr high entropy alloy with a hitherto unique structure. A phase diagram analysis narrows down the large compositional space to a well-defined set of candidates. First-principles calculations demonstrate the energetic preference of an ordered superstructure over the competing disordered solid solutions. The chief ingredient is the Al concentration, which can be tuned to achieve a D019 ordering on the hexagonal lattice. The computationally designed D019 superstructure is experimentally confirmed by transmission electron microscopy and X-ray studies. Our scheme enables the exploration of a new class of high entropy alloys.
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Affiliation(s)
- Lukasz Rogal
- Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 30-059, Krakow, Poland.
| | - Piotr Bobrowski
- Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 30-059, Krakow, Poland
| | - Fritz Körmann
- Materials Science and Engineering, Delft University of Technology, 2628, CD, Delft, Netherlands
| | - Sergiy Divinski
- Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Str. 10, 48149, Münster, Germany
| | - Frank Stein
- Max-Planck-Institut für Eisenforschung GmbH D-40237, Düsseldorf, Germany
| | - Blazej Grabowski
- Max-Planck-Institut für Eisenforschung GmbH D-40237, Düsseldorf, Germany.
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Belozerov AS, Poteryaev AI, Skornyakov SL, Anisimov VI. Structural γ-ε phase transition in Fe-Mn alloys from a CPA + DMFT approach. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:465601. [PMID: 26496785 DOI: 10.1088/0953-8984/27/46/465601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a computational scheme for total energy calculations of disordered alloys with strong electronic correlations. It employs the coherent potential approximation combined with the dynamical mean-field theory and allows one to study the structural transformations. The material-specific Hamiltonians in the Wannier function basis are obtained by density functional theory. The proposed computational scheme is applied to study the γ-ε structural transition in paramagnetic Fe-Mn alloys for Mn content from 10 to 20 at.%. The electronic correlations are found to play a crucial role in this transition. The calculated transition temperature decreases with increasing Mn content and is in good agreement with experiment. We demonstrate that in contrast to the α-γ transition in pure iron, the γ-ε transition in Fe-Mn alloys is driven by a combination of kinetic and Coulomb energies. The latter is found to be responsible for the decrease of the γ-ε transition temperature with Mn content.
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Affiliation(s)
- A S Belozerov
- Miheev Institute of Metal Physics, Russian Academy of Sciences, 620137 Yekaterinburg, Russia. Ural Federal University, 620002 Yekaterinburg, Russia
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12
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Gruner ME, Keune W, Roldan Cuenya B, Weis C, Landers J, Makarov SI, Klar D, Hu MY, Alp EE, Zhao J, Krautz M, Gutfleisch O, Wende H. Element-resolved thermodynamics of magnetocaloric LaFe(13-x)Si(x). PHYSICAL REVIEW LETTERS 2015; 114:057202. [PMID: 25699465 DOI: 10.1103/physrevlett.114.057202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 06/04/2023]
Abstract
By combination of two independent approaches, nuclear resonant inelastic x-ray scattering and first-principles calculations in the framework of density functional theory, we demonstrate significant changes in the element-resolved vibrational density of states across the first-order transition from the ferromagnetic low temperature to the paramagnetic high temperature phase of LaFe(13-x)Si(x). These changes originate from the itinerant electron metamagnetism associated with Fe and lead to a pronounced magneto-elastic softening despite the large volume decrease at the transition. The increase in lattice entropy associated with the Fe subsystem is significant and contributes cooperatively with the magnetic and electronic entropy changes to the excellent magneto- and barocaloric properties.
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Affiliation(s)
- M E Gruner
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany and IFW Dresden P.O. Box 270116, 01171 Dresden, Germany
| | - W Keune
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany and Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | - B Roldan Cuenya
- Department of Physics, Ruhr-University Bochum, 44780 Bochum, Germany
| | - C Weis
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - J Landers
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - S I Makarov
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany and Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | - D Klar
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - M Y Hu
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E E Alp
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Zhao
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M Krautz
- IFW Dresden P.O. Box 270116, 01171 Dresden, Germany
| | - O Gutfleisch
- Materials Science, TU Darmstadt, 64287 Darmstadt, Germany
| | - H Wende
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
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Chen W, Dalach P, Schneider WF, Wolverton C. Interplay between subsurface ordering, surface segregation, and adsorption on Pt-Ti(111) near-surface alloys. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4683-4693. [PMID: 22352380 DOI: 10.1021/la204843q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Using the first-principles cluster expansion (CE) method, we studied the subsurface ordering of Pt/Pt-Ti(111) surface alloys and the effect of this ordering on segregation and adsorption behavior. The clusters included in the CE are optimized by a genetic algorithm to better describe the interactions between Pt and Ti atoms in the subsurface layer. Similar to bulk Pt-Ti alloys, Pt-Ti(111) subsurface alloys show a strong ordering tendency. A series of stable ordered Pt-Ti subsurface structures are identified from the two-dimensional (2D) CE. As an indication of the connection between the 2D and the bulk ordering, the CE predicts a ground-state Pt(8)Ti structure in the (111) subsurface layer, which is the same ordering as the close-packed plane of the bulk Pt(8)Ti compound. We carried out Monte Carlo simulations (MC) using the CE Hamiltonian to study the finite temperature stability of the Pt-Ti subsurface structures. The MC results show that subsurface structures in the Pt-rich range have higher order-disorder transition temperatures than their Ti-rich subsurface counterparts. We calculate the binding energy of different adsorbates (O, S, H, and NO) on Pt-terminated and Ti-segregated surfaces of ordered PtTi and Pt(8)Ti subsurface alloys. The binding of these adsorbates is generally stronger on Ti-segregated surfaces than Pt-terminated surfaces. The adsorption-induced Ti surface segregation is determined by two factors: (i) the unfavorable energy penalty for the Ti atom to segregate to the clean surface and (ii) the favorable energy decrease from stronger adsorbate binding on the Ti-segregated surface. The two factors introduce similar magnitude in energy change for the S and NO adsorption on Ti-segregated surfaces of PtTi subsurface alloys. We predict an adsorption-induced Ti surface segregation that is dependent on the atomic configurations of the Ti-segregated surfaces resulting from the competition of the two factors.
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Affiliation(s)
- Wei Chen
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
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Zhou F, Maxisch T, Ceder G. Configurational electronic entropy and the phase diagram of mixed-valence oxides: the case of LixFePO4. PHYSICAL REVIEW LETTERS 2006; 97:155704. [PMID: 17155339 DOI: 10.1103/physrevlett.97.155704] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Indexed: 05/12/2023]
Abstract
We demonstrate that configurational electronic entropy, previously neglected, in ab initio thermodynamics of materials can qualitatively modify the finite-temperature phase stability of mixed-valence oxides. While transformations from low-T ordered or immiscible states are almost always driven by configurational disorder (i.e., random occupation of lattice sites by multiple species), in FePO4-LiFePO4 the formation of a solid solution is almost entirely driven by electronic rather than ionic configurational entropy. We argue that such an electronic entropic mechanism may be relevant to most other mixed-valence systems.
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Affiliation(s)
- Fei Zhou
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Geng HY, Sluiter MHF, Chen NX. Cluster expansion of electronic excitations: Application to fcc Ni–Al alloys. J Chem Phys 2005; 122:214706. [PMID: 15974761 DOI: 10.1063/1.1926276] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The cluster expansion method is applied to electronic excitations and a set of effective cluster densities of states (ECDOS) is defined, analogous to effective cluster interactions (ECIs). The ECDOSs are used to generate alloy thermodynamic properties as well as the equation of state (EOS) of electronic excitations for the fcc Ni-Al systems. When parent clusters have a small size, the convergence of the expansion is not so good but the electronic density of state (DOS) is well reproduced. However, the integrals of the DOS such as the cluster expanded free energy, entropy, and internal energy associated with electronic excitations are well described at the level of the tetrahedron-octahedron cluster approximation, indicating that the ECDOS is applicable to produce electronic ECIs for cluster variation method (CVM) or Monte Carlo calculations. On the other hand, the Gruneisen parameter, calculated with first-principles methods, is no longer a constant and implies that the whole DOS profile should be considered for EOS of electronic excitations, where ECDOS adapts very well for disordered alloys and solid solutions.
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Affiliation(s)
- H Y Geng
- Department of Physics, Tsinghua University, Beijing 100084, China.
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Zarkevich NA, Johnson DD. Reliable first-principles alloy thermodynamics via truncated cluster expansions. PHYSICAL REVIEW LETTERS 2004; 92:255702. [PMID: 15245032 DOI: 10.1103/physrevlett.92.255702] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2003] [Indexed: 05/24/2023]
Abstract
In alloys cluster expansions (CE) are increasingly used to combine first-principles electronic-structure calculations and Monte Carlo methods to predict thermodynamic properties. As a basis-set expansion in terms of lattice geometrical clusters and effective cluster interactions, the CE is exact if infinite, but is tractable only if truncated. Yet until now a truncation procedure was not well defined and did not guarantee a reliable truncated CE. We present an optimal truncation procedure for CE basis sets that provides reliable thermodynamics. We then exemplify its importance in Ni3V, where the CE has failed unpredictably, and now show agreement to a range of measured values, predict new low-energy structures, and explain the cause of previous failures.
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Affiliation(s)
- Nikolai A Zarkevich
- Departments of Physics and Materials Science & Engineering, and Frederich Seitz Materials Research Laboratory, University of Illinois, Urbana-Champaign, IL 61801, USA.
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Wolverton C, Zunger A, Froyen S, Wei S. Point-charge electrostatics in disordered alloys. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:7843-7856. [PMID: 9984459 DOI: 10.1103/physrevb.54.7843] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cabet E, Pasturel A, Ducastelle F, Loiseau A. L12-D022 competition in the pseudobinary (Pt, Rh)3V, Pt3(V, Ti), and (Pd, Rh)3V alloys: Phase stability and electronic structure. PHYSICAL REVIEW LETTERS 1996; 76:3140-3143. [PMID: 10060885 DOI: 10.1103/physrevlett.76.3140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Garbulsky GD, Ceder G. Contribution of the vibrational free energy to phase stability in substitutional alloys: Methods and trends. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:8993-9001. [PMID: 9982401 DOI: 10.1103/physrevb.53.8993] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Lebacq O, Pasturel A, Finel A, Caudron R, Barrachin M. Ab initio analysis of structural stability in the compound Ni3V. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:6203-6208. [PMID: 9982019 DOI: 10.1103/physrevb.53.6203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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