Imperial College London

DrSergeiDudarev

Faculty of Natural SciencesDepartment of Physics

Visiting Professor
 
 
 
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Contact

 

+44 (0)1235 465 203s.dudarev

 
 
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Location

 

811Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

66 results found

Fedorov M, Wróbel JS, London AJ, Kurzydłowski KJ, Fu CC, Tadić T, Dudarev SL, Nguyen-Manh Det al., 2023, Precipitation of Cr-rich clusters in Fe-Cr alloys: Effects of irradiation from first principles modeling and experimental observations, Journal of Nuclear Materials, Vol: 587, ISSN: 0022-3115

Using exchange Monte Carlo (MC) simulations based on an ab initio-parameterized Cluster Expansion (CE) model, we explore the phase stability of low-Cr Fe-Cr alloys as a function of vacancy (Vac), carbon, and nitrogen content. To parameterize the CE model, we perform Density Functional Theory calculations for more than 1600 supercells containing Cr-Vac-C-N clusters of various sizes in pure bcc Fe, Cr, and Fe-Cr alloys. MC simulations performed for T=650 K show that Cr clustering in Fe-3.28 at.%Cr alloys does not occur if there are no defects or if only vacancies are present. But the addition of a small amount of C or N, at the level as low as 0.02 at.% in an alloy with no vacancies, routinely results in the formation of ordered compounds containing a high amount of Cr, C and N. Cr segregates to interstitial atoms and Cr content in such Cr-rich clusters increases as a function of C and/or N concentration. In the presence of vacancies, C/N aggregate to the core regions of vacancy clusters, making segregation of Cr-rich clusters less pronounced. The structure of Cr-rich clusters varies significantly, depending on the concentration of interstitial atoms and on the ratio of N to C. Predictions derived from MC simulations agree with experimental observations of Fe-Cr alloys exposed to ion irradiation. The concentration of Cr found in clusters containing C and N interstitial atoms is in qualitative agreement, and the absolute Cr content found in the clusters simulated at 650 K is in quantitative agreement with experimental Atom Probe Tomography (APT) observations of Fe-3.28 at.%Cr alloys irradiated at 623 K. The measured C and N content of 42±5 and 151±3 atomic ppm likely results from the contamination that occurred during ion beam irradiation.

Journal article

Wells T, Foulkes W, Dudarev S, Horsfield AHet al., 2023, The Einstein-de Haas effect in an Fe₁₅ cluster, Journal of Physics: Condensed Matter, Vol: 35, Pages: 1-16, ISSN: 0953-8984

Classical models of spin-lattice coupling are at present unable to accurately reproduce results for numerous properties of ferromagnetic materials, such as heat transport coefficients or the sudden collapse of the magnetic moment in hcp-Fe under pressure. This failure has been attributed to the absence of a proper treatment of effects that are inherently quantum mechanical in nature, notably spin-orbit coupling. This paper introduces a time-dependent, non-collinear tight binding model, complete with spin-orbit coupling and vector Stoner exchange terms, that is capable of simulating the Einstein-de Haas effect in a ferromagnetic Fe15 cluster. The tight binding model is used to investigate the adiabaticity timescales that determine the response of the orbital and spin angular momenta to a rotating, externally applied Β field, and we show that the qualitative behaviours of our simulations can be extrapolated to realistic timescales by use of the adiabatic theorem. 
An analysis of the trends in the torque contributions with respect to the field strength demonstrates that SOC is necessary to observe a transfer of angular momentum from the electrons to the nuclei at experimentally realistic Β fields.
The simulations presented in this paper demonstrate the Einstein-de Haas effect from first principles using a Fe cluster.

Journal article

Ma P-W, Mason DR, Van Boxel S, Dudarev SLet al., 2023, Athermal evolution of nanocrystalline tungsten driven by irradiation, JOURNAL OF NUCLEAR MATERIALS, Vol: 586, ISSN: 0022-3115

Journal article

Reali L, Gilbert MR, Boleininger M, Dudarev SLet al., 2023, γ-photons and high-energy electrons produced by neutron irradiation in nuclear materials, JOURNAL OF NUCLEAR MATERIALS, Vol: 585, ISSN: 0022-3115

Journal article

Warwick AR, Thomas R, Boleininger M, Koc O, Zilahi G, Ribarik G, Hegedues Z, Lienert U, Ungar T, Race C, Preuss M, Frankel P, Dudarev SLet al., 2023, Dislocation density transients and saturation in irradiated zirconium, INTERNATIONAL JOURNAL OF PLASTICITY, Vol: 164, ISSN: 0749-6419

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Boleininger M, Mason DR, Sand AE, Dudarev SLet al., 2023, Microstructure of a heavily irradiated metal exposed to a spectrum of atomic recoils, SCIENTIFIC REPORTS, Vol: 13, ISSN: 2045-2322

Journal article

Boleininger M, Dudarev SL, Mason DR, Martinez Eet al., 2022, Volume of a dislocation network, PHYSICAL REVIEW MATERIALS, Vol: 6, ISSN: 2475-9953

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Reali L, Boleininger M, Gilbert MR, Dudarev SLet al., 2022, Macroscopic elastic stress and strain produced by irradiation, NUCLEAR FUSION, Vol: 62, ISSN: 0029-5515

Journal article

Warwick AR, Boleininger M, Dudarev SL, 2021, Microstructural complexity and dimensional changes in heavily irradiated zirconium, PHYSICAL REVIEW MATERIALS, Vol: 5, ISSN: 2475-9953

Journal article

Gilbert MR, Arakawa K, Bergstrom Z, Caturla MJ, Dudarev SL, Gao F, Goryaeva AM, Hu SY, Hu X, Kurtz RJ, Litnovsky A, Marian J, Marinica M-C, Martinez E, Marquis EA, Mason DR, Nguyen BN, Olsson P, Osetskiy Y, Senor D, Setyawan W, Short MP, Suzudo T, Trelewicz JR, Tsuru T, Was GS, Wirth BD, Yang L, Zhang Y, Zinkle SJet al., 2021, Perspectives on multiscale modelling and experiments to accelerate materials development for fusion, JOURNAL OF NUCLEAR MATERIALS, Vol: 554, ISSN: 0022-3115

Journal article

Mason DR, Granberg F, Boleininger M, Schwarz-Selinger T, Nordlund K, Dudarev SLet al., 2021, Parameter-free quantitative simulation of high-dose microstructure and hydrogen retention in ion-irradiated tungsten, PHYSICAL REVIEW MATERIALS, Vol: 5, ISSN: 2475-9953

Journal article

Ma P-W, Dudarev SL, 2021, Elastic dipole tensor of a defect at a finite temperature: Definition and properties, PHYSICAL REVIEW MATERIALS, Vol: 5, ISSN: 2475-9953

Journal article

Wrobel JS, Zemla MR, Nguyen-Manh D, Olsson P, Messina L, Domain C, Wejrzanowski T, Dudarev SLet al., 2021, Elastic dipole tensors and relaxation volumes of point defects in concentrated random magnetic Fe-Cr alloys, COMPUTATIONAL MATERIALS SCIENCE, Vol: 194, ISSN: 0927-0256

Journal article

Duc N-M, Wrobel JS, Klimenkov M, Lloyd MJ, Messina L, Dudarev SLet al., 2021, First-principles model for voids decorated by transmutation solutes: Short-range order effects and application to neutron irradiated tungsten, PHYSICAL REVIEW MATERIALS, Vol: 5, ISSN: 2475-9953

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Ma P-W, Dudarev SL, 2021, Nonuniversal structure of point defects in face-centered cubic metals, PHYSICAL REVIEW MATERIALS, Vol: 5, ISSN: 2475-9953

Journal article

Mason DR, Das S, Derlet PM, Dudarev SL, London AJ, Yu H, Phillips NW, Yang D, Mizohata K, Xu R, Hofmann Fet al., 2020, Observation of Transient and Asymptotic Driven Structural States of Tungsten Exposed to Radiation, PHYSICAL REVIEW LETTERS, Vol: 125, ISSN: 0031-9007

Journal article

Ma P-W, Mason DR, Dudarev SL, 2020, Multiscale analysis of dislocation loops and voids in tungsten, PHYSICAL REVIEW MATERIALS, Vol: 4, ISSN: 2475-9953

Journal article

Ma P-W, Dudarev SL, 2020, CALANIE: Anisotropic elastic correction to the total energy, to mitigate the effect of periodic boundary conditions, COMPUTER PHYSICS COMMUNICATIONS, Vol: 252, ISSN: 0010-4655

Journal article

Arakawa K, Marinica M-C, Fitzgerald S, Proville L, Duc N-M, Dudarev SL, Ma P-W, Swinburne TD, Goryaeva AM, Yamada T, Amino T, Arai S, Yamamoto Y, Higuchi K, Tanaka N, Yasuda H, Yasuda T, Mori Het al., 2020, Quantum de-trapping and transport of heavy defects in tungsten, NATURE MATERIALS, Vol: 19, Pages: 508-+, ISSN: 1476-1122

Journal article

Mason DR, Duc N-M, Marinica M-C, Alexander R, Sand AE, Dudarev SLet al., 2019, Relaxation volumes of microscopic and mesoscopic irradiation-induced defects in tungsten, JOURNAL OF APPLIED PHYSICS, Vol: 126, ISSN: 0021-8979

Journal article

Dudarev SL, Liu P, Andersson DA, Stanek CR, Ozaki T, Franchini Cet al., 2019, Parametrization of LSDA plus U for noncollinear magnetic configurations: Multipolar magnetism in UO2, Physical Review Materials, Vol: 3, Pages: 1-14, ISSN: 2475-9953

To explore the formation of noncollinear magnetic configurations in materials with strongly correlated electrons, we derive a noncollinear LSDA+U model involving only one parameter U, as opposed to the difference between the Hubbard and Stoner parameters U−J. Computing U in the constrained random phase approximation, we investigate noncollinear magnetism of uranium dioxide UO2 and find that the spin-orbit coupling (SOC) stabilizes the 3k ordered magnetic ground state. The estimated SOC strength in UO2 is as large as 0.73 eV per uranium atom, making spin and orbital degrees of freedom virtually inseparable. Using a multipolar pseudospin Hamiltonian, we show how octupolar and dipole-dipole exchange coupling help establish the 3k magnetic ground state with canted ordering of uranium f orbitals. The cooperative Jahn-Teller effect does not appear to play a significant part in stabilizing the noncollinear 3k state, which has the lowest energy even in an undistorted lattice. The choice of parameter U in the LSDA+U model has a notable quantitative effect on the predicted properties of UO2, in particular on the magnetic exchange interaction and, perhaps trivially, on the band gap: The value of U=3.46eV computed fully ab initio delivers the band gap of 2.11 eV in good agreement with experiment, and a balanced account of other pertinent energy scales.

Journal article

Mason DR, Sand AE, Dudarev SL, 2019, Atomistic-object kinetic Monte Carlo simulations of irradiation damage in tungsten, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, Vol: 27, ISSN: 0965-0393

Journal article

Wells T, Horsfield A, Foulkes WMC, Dudarev Set al., 2019, The microscopic Einstein-de Haas effect, Journal of Chemical Physics, Vol: 150, ISSN: 0021-9606

The Einstein-de Haas (EdH) effect, where the spin angular momentum of electrons is transferred to the mechanical angular momentum of atoms, was established experimentally in 1915. While a semiclassical explanation of the effect exists, modern electronic structure methods have not yet been applied to model the phenomenon. In this paper, we investigate its microscopic origins by means of a noncollinear tight-binding model of an O2 dimer, which includes the effects of spin-orbit coupling, coupling to an external magnetic field, and vector Stoner exchange. By varying an external magnetic field in the presence of spin-orbit coupling, a torque can be generated on the dimer, validating the presence of the EdH effect. The avoided energy level crossings and the rate of change of magnetic field determine the evolution of the spin. We also find that the torque exerted on the nuclei by the electrons in a time-varying B field is not only due to the EdH effect. The other contributions arise from field-induced changes in the electronic orbital angular momentum and from the direct action of the Faraday electric field associated with the time-varying magnetic field.

Journal article

Ma P-W, Dudarev SL, 2019, Effect of stress on vacancy formation and migration in body-centered-cubic metals, PHYSICAL REVIEW MATERIALS, Vol: 3, ISSN: 2475-9953

Journal article

Ma P-W, Dudarev SL, 2019, Symmetry-broken self-interstitial defects in chromium, molybdenum, and tungsten, PHYSICAL REVIEW MATERIALS, Vol: 3, ISSN: 2475-9953

Journal article

Ma P-W, Dudarev SL, 2019, Universality of point defect structure in body-centered cubic metals, PHYSICAL REVIEW MATERIALS, Vol: 3, ISSN: 2475-9953

Journal article

Dudarev SL, Mason DR, Tarleton E, Ma P-W, Sand AEet al., 2018, A multi-scale model for stresses, strains and swelling of reactor components under irradiation, NUCLEAR FUSION, Vol: 58, ISSN: 0029-5515

Journal article

Rovelli I, Dudarev SL, Sutton AP, 2018, Statistical model for diffusion-mediated recovery of dislocation and point-defect microstructure, Physical Review E, Vol: 98, ISSN: 1539-3755

The evolution of the defect microstructure in materials at high temperature is dominated by diffusion-mediated interactions between dislocations, cavities, and surfaces. This gives rise to complex nonlinear couplings between interstitial and vacancy-type dislocation loops, cavities, and the field of diffusing vacancies that adiabatically follows the evolution of microstructure. In our previous work, we developed a nonlocal model for the climb of curved dislocations and the morphological evolution of cavities during postirradiation annealing of structural components in nuclear reactors. We now expand the formalism to include the treatment of population of very small defects and dislocation loops that are below the experimental detection limit. These are taken into account through a mean field approach coupled with an explicit real-space treatment of larger-scale discrete defect clusters. We find that randomly distributed small defects screen diffusive interactions between larger discrete clusters, renormalizing the free diffusion Green's functions and transforming them into Yukawa-type propagators. The evolution of the coupled system is modelled self-consistently, showing how the defect microstructure evolves through a nonmonotonic variation of the distribution of sizes of dislocation loops and cavities, treated as discrete real-space objects.

Journal article

Coury MEA, Dudarev SL, Foulkes WMC, Horsfield AP, Ma P-W, Spencer JSet al., 2018, Erratum: Hubbard-like Hamiltonians for interacting electrons in s, p, and d orbitals (vol 93, 075101, 2016), Physical Review B, Vol: 98, ISSN: 2469-9950

Journal article

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