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Mikhaylushkin, Arkady S.
Alternative names
Publications (10 of 25) Show all publications
Ekholm, M., Mikhaylushkin, A., Simak, S., Johansson, B. & Abrikosov, I. (2011). Configurational thermodynamics of Fe-Ni alloys at Earths core conditions. Earth and Planetary Science Letters, 308(1-2), 90-96
Open this publication in new window or tab >>Configurational thermodynamics of Fe-Ni alloys at Earths core conditions
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2011 (English)In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 308, no 1-2, p. 90-96Article in journal (Refereed) Published
Abstract [en]

By means of ab-initio calculations, we perform an analysis of the configurational thermodynamics, effects of disorder, and structural energy differences in Fe-Ni alloys at the pressure and temperature conditions of the Earths core. We show from ab-initio calculations that the ordering energies of fcc and hcp-structured Fe-Ni solid solutions at these conditions depend sensitively on the alloy configuration, i.e., on the degree of chemical disorder, and are on a scale comparable with the structural energy differences. From configurational thermodynamic simulations we find that a distribution of Fe and Ni atoms in the solutions should be very close to completely disordered at these conditions. Using this model of the Fe-Ni system, we have calculated the fcc-hcp structural free energy difference in a wide pressure-temperature range of 120-360 GPa and 1000-6600K. Our calculations show that alloying of Fe with Ni below 3000 K favours stabilisation of the fcc phase over the hcp, in agreement with experiments. However, above 3000 K the effect is reversed, and at conditions corresponding to those of the Earths inner core, Ni acts as an agent to stabilise the hcp phase.

Place, publisher, year, edition, pages
Elsevier, 2011
Keyword
Earths inner core, Fe-Ni alloy, ab-initio calculations, crystal structure
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-70218 (URN)10.1016/j.epsl.2011.05.035 (DOI)000293486100009 ()
Note
Original Publication: Marcus Ekholm, Arkady Mikhaylushkin, Sergey Simak, B Johansson and Igor Abrikosov, Configurational thermodynamics of Fe-Ni alloys at Earths core conditions, 2011, Earth and Planetary Science Letters, (308), 1-2, 90-96. http://dx.doi.org/10.1016/j.epsl.2011.05.035 Copyright: Elsevier http://www.elsevier.com/Available from: 2011-08-26 Created: 2011-08-26 Last updated: 2017-12-08Bibliographically approved
Mondal, S., van Smaalen, S., Schoenleber, A., Filinchuk, Y., Chernyshov, D., Simak, S., . . . Dubrovinskaia, N. (2011). Electron-Deficient and Polycenter Bonds in the High-Pressure gamma-B-28 Phase of Boron. PHYSICAL REVIEW LETTERS, 106(21), 215502
Open this publication in new window or tab >>Electron-Deficient and Polycenter Bonds in the High-Pressure gamma-B-28 Phase of Boron
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2011 (English)In: PHYSICAL REVIEW LETTERS, ISSN 0031-9007, Vol. 106, no 21, p. 215502-Article in journal (Refereed) Published
Abstract [en]

The peculiar bonding situation in gamma boron is characterized on the basis of an experimental electron-density distribution which is obtained by multipole refinement against low-temperature single-crystal x-ray diffraction data. A topological analysis of the electron-density distribution reveals one-electron-two-center bonds connecting neighboring icosahedral B-12 clusters. A unique polar-covalent two-electron-three-center bond between a pair of atoms of an icosahedral cluster and one atom of the interstitial B-2 dumbbell explains the observed charge separation in this high-pressure high-temperature polymorph of boron.

Place, publisher, year, edition, pages
American Physical Society, 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-68901 (URN)10.1103/PhysRevLett.106.215502 (DOI)000290940200010 ()
Note
Original Publication: Swastik Mondal, Sander van Smaalen, Andreas Schoenleber, Yaroslav Filinchuk, Dmitry Chernyshov, Sergey Simak, Arkady Mikhaylushkin, Igor Abrikosov, Evgeniya Zarechnaya, Leonid Dubrovinsky and Natalia Dubrovinskaia, Electron-Deficient and Polycenter Bonds in the High-Pressure gamma-B-28 Phase of Boron, 2011, PHYSICAL REVIEW LETTERS, (106), 21, 215502. http://dx.doi.org/10.1103/PhysRevLett.106.215502 Copyright: American Physical Society http://www.aps.org/ Available from: 2011-06-10 Created: 2011-06-10 Last updated: 2011-06-21
Lane, N. J., Simak, S., Mikhaylushkin, A., Abrikosov, I., Hultman, L. & Barsoum, M. W. (2011). First-principles study of dislocations in hcp metals through the investigation of the (11(2)over-bar1) twin boundary. Physical Review B. Condensed Matter and Materials Physics, 84(18), 184101
Open this publication in new window or tab >>First-principles study of dislocations in hcp metals through the investigation of the (11(2)over-bar1) twin boundary
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2011 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 84, no 18, p. 184101-Article in journal (Refereed) Published
Abstract [en]

Herein, we use first principles calculations to study the energy of the (11 (2) over bar1) twin boundary in Zr, Zn, Mg, Ti, and Be. This boundary is important for understanding the microyielding and damping of hexagonal close-packed metals. The (11 (2) over bar1) twin boundary is unique in that it is composed of-and can form by the glide of-basal dislocations nucleating at every c lattice parameter. The effect of the number of atoms between boundaries on the boundary energy, and the resulting lattice strains of the relaxed structures are quantified. It is shown that the energies obtained converge within 32-64 atoms/supercell. The structures with a higher second-order elastic constant term, c(44), also have higher boundary energies. It is further shown that the critical resolved shear stresses of the basal dislocations at 0 K, which make up the (11 (2) over bar1) twin, are so low as to be below the threshold of the first principles calculations.

Place, publisher, year, edition, pages
American Physical Society, 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-72652 (URN)10.1103/PhysRevB.84.184101 (DOI)000296862800003 ()
Note
Funding Agencies|National Science Foundation|DGE-0654313|Foundation for Strategic Research (SSF)||Research Council (VR)||Government Strategic Research Area Grant in Materials Science||Available from: 2011-12-02 Created: 2011-12-02 Last updated: 2017-12-08
Isaev, E., Simak, S., Mikhaylushkin, A., Vekilov, Y. K. K., Zarechnaya, E. Y., Dubrovinsky, L., . . . Abrikosov, I. (2011). Impact of lattice vibrations on equation of state of the hardest boron phase. Physical Review B. Condensed Matter and Materials Physics, 83(13), 132106
Open this publication in new window or tab >>Impact of lattice vibrations on equation of state of the hardest boron phase
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2011 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, no 13, p. 132106-Article in journal (Refereed) Published
Abstract [en]

An accurate equation of state (EOS) is determined for the high-pressure orthorhombic phase of boron, B(28), experimentally as well as from ab initio calculations. The unique feature of our experiment is that it is carried out on the single crystal of B(28). In theory, we take into consideration the lattice vibrations, often neglected in first-principles simulations. We show that the phonon contribution has a profound effect on the EOS of B(28), giving rise to anomalously low values of the pressure derivative of the bulk modulus and greatly improving the agreement between theory and experiment.

Place, publisher, year, edition, pages
American Physical Society, 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-69916 (URN)10.1103/PhysRevB.83.132106 (DOI)000292142300003 ()
Note
Original Publication: Eyvas Isaev, Sergey Simak, Arkady Mikhaylushkin, Yu. Kh. Vekilov, E. Yu. Zarechnaya, L. Dubrovinsky, N. Dubrovinskaia, M. Merlini, M. Hanfland and Igor Abrikosov, Impact of lattice vibrations on equation of state of the hardest boron phase, 2011, Physical Review B. Condensed Matter and Materials Physics, (83), 13, 132106. http://dx.doi.org/10.1103/PhysRevB.83.132106 Copyright: American Physical Society http://www.aps.org/ Available from: 2011-08-09 Created: 2011-08-08 Last updated: 2017-12-08
Haeussermann, U. & Mikhaylushkin, A. (2010). Electron-poor antimonides: complex framework structures with narrow band gaps and low thermal conductivity. Dalton Transactions, 39(4), 1036-1045
Open this publication in new window or tab >>Electron-poor antimonides: complex framework structures with narrow band gaps and low thermal conductivity
2010 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 39, no 4, p. 1036-1045Article in journal (Refereed) Published
Abstract [en]

Binary zinc and cadmium antimonides and their ternary relatives with indium display complex crystal structures, but reveal at the same time narrow band gaps in their electronic structure at or close to the Fermi level. It is argued that these systems represent "electron-poor framework semiconductors" (EPFS) with average valence electron concentrations between three and four. EPFS materials constituted of metal and semimetal atoms form a common, weakly polar framework containing multi-center bonded structural entities. The localized multi-center bonding feature is thought to be the key to structurally complex semiconductors. In this respect electron-poor antimonides become related to modifications of elemental boron. Electron-poor antimonides show promising thermoelectric properties, especially through a remarkably low thermal conductivity. At the same time the thermal stability of these compounds is rather limited because of temperature polymorphism and/or comparatively low melting or decomposition temperatures ( usually below 600 K).

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2010
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-58483 (URN)10.1039/b915724g (DOI)000273518400009 ()
Available from: 2010-08-11 Created: 2010-08-11 Last updated: 2017-12-12
Burakovsky, L., Chen, S. P., Preston, D. L., Belonoshko, A. B., Rosengren, A., Mikhaylushkin, A., . . . Moriarty, J. A. (2010). High-Pressure-High-Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy. Physical Review Letters, 104(25), 255702
Open this publication in new window or tab >>High-Pressure-High-Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy
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2010 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 104, no 25, p. 255702-Article in journal (Refereed) Published
Abstract [en]

Phase diagrams of refractory metals remain essentially unknown. Moreover, there is an ongoing controversy over the high-pressure melting temperatures of these metals: results of diamond anvil cell (DAC) and shock wave experiments differ by at least a factor of 2. From an extensive ab initio study on tantalum we discovered that the body-centered cubic phase, its physical phase at ambient conditions, transforms to another solid phase, possibly hexagonal omega phase, at high temperature. Hence the sample motion observed in DAC experiments is very likely not due to melting but internal stresses accompanying a solid-solid transformation, and thermal stresses associated with laser heating.

Place, publisher, year, edition, pages
American Physical Society, 2010
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-58287 (URN)10.1103/PhysRevLett.104.255702 (DOI)000279036300002 ()
Note
Original Publication: L. Burakovsky, S. P. Chen, D. L. Preston, A. B. Belonoshko, A. Rosengren, Arkady Mikhaylushkin, Sergey Simak and J. A. Moriarty, High-Pressure-High-Temperature Polymorphism in Ta: Resolving an Ongoing Experimental Controversy, 2010, Physical Review Letters, (104), 25, 255702. http://dx.doi.org/10.1103/PhysRevLett.104.255702 Copyright: American Physical Society http://www.aps.org/ Available from: 2010-08-10 Created: 2010-08-09 Last updated: 2017-12-12
Haeusserman, U. & Mikhaylushkin, A. (2010). Structure and Bonding of gamma-B-28: Is the High Pressure Form of Elemental Boron Ionic?. INORGANIC CHEMISTRY, 49(24), 11270-11275
Open this publication in new window or tab >>Structure and Bonding of gamma-B-28: Is the High Pressure Form of Elemental Boron Ionic?
2010 (English)In: INORGANIC CHEMISTRY, ISSN 0020-1669, Vol. 49, no 24, p. 11270-11275Article in journal (Refereed) Published
Abstract [en]

The recently characterized crystal structure of metastable gamma-B-28 is analyzed from a crystal chemical point of view, and the electron requirement of its building units and that of their linkage is determined. The structure consists of unique B-2 dumbbells and B-12 icosahedra, which are connected through two-center and three-center, two-electron bonds. The different bonding motifs are ascertained by theoretical calculations of difference charge distributions. Chemical bonding in high pressure gamma-B-28 bears great resemblance to alpha-B-12 which is the simplest boron modification. The previously made description of gamma-B-28 as ionic in terms of (B2)(delta+) and (B-12)(delta-) is not supported.

Place, publisher, year, edition, pages
ACS American Chemical Society, 2010
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-64387 (URN)10.1021/ic101266d (DOI)000285266800004 ()
Available from: 2011-01-21 Created: 2011-01-21 Last updated: 2011-01-21
Mikhaylushkin, A. S. (2010). The influence of hydrogen contamination on the structural stability of CoSn under compression. JOURNAL OF PHYSICS-CONDENSED MATTER, 22(43), 435501
Open this publication in new window or tab >>The influence of hydrogen contamination on the structural stability of CoSn under compression
2010 (English)In: JOURNAL OF PHYSICS-CONDENSED MATTER, ISSN 0953-8984, Vol. 22, no 43, p. 435501-Article in journal (Refereed) Published
Abstract [en]

The binary CoSn compound has a unique ground state large-void crystal structure, whose stability under pressure has recently been examined. Whereas theoretical results predicted a series of phase transformations, the room temperature experiments did not observe any structural change. We suggest that the large void of a CoSn-type structure could contain natural impurities such as hydrogen, which can influence the thermodynamic stability of a CoSn system and explain the unusual disagreement between the theoretical and experimental results. Based on first-principles calculations we reveal that the contamination of CoSn by hydrogen only results in a subtle change of structural parameters and the equation of state of CoSn, but drastically increases the stability of the CoSn-type phase in comparison with the high-pressure phases predicted earlier. We argue that the hardly detectable natural impurities of light elements in porous compounds like CoSn are able to change the phase equilibria.

Place, publisher, year, edition, pages
Iop Publishing Ltd, 2010
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-60884 (URN)10.1088/0953-8984/22/43/435501 (DOI)000282749400009 ()
Available from: 2010-10-29 Created: 2010-10-29 Last updated: 2010-10-29
Ghafoor, N., Eriksson, F., Mikhaylushkin, A., Abrikosov, I., Gullikson, E. M., Beckers, M., . . . Birch, J. (2009). Effects of O and N impurities on the nanostructural evolution during growth of Cr/Sc multilayers. Journal of Materials Research, 24(1), 79-95
Open this publication in new window or tab >>Effects of O and N impurities on the nanostructural evolution during growth of Cr/Sc multilayers
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2009 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 24, no 1, p. 79-95Article in journal (Refereed) Published
Abstract [en]

Transition metal multilayers are prime candidates for high reflectivity soft x-ray multilayer mirrors. In particular, Cr/Sc multilayers in the amorphous state have proven to give the highest reflectivity in the water window. We have investigated the influence of impurities N and O as residual gas elements on the growth, structure, and optical performance of Cr/Sc multilayers deposited in high vacuum conditions by a dual cathode direct current magnetron sputter deposition. Multilayer structures with the modulation periods in the range of 0.9–4.5 nm and Cr layer to bilayer thickness ratios in the range of 0.17–0.83 were deposited with an intentionally raised base pressure (pB), ranging from 2 × 10-7 to 2 × 10-5 Torr. Compositional depth profiles were obtained by elastic recoil detection analysis and Rutherford backscattering spectroscopy, while the structural investigations of the multilayers were carried out using hard x-ray reflectivity and transmission electron microscopy. By investigating stacked multilayers, i.e., several multilayers with different designs of the modulation periods, stacked on top of each other in the samples, we have been able to conclude that both N and O are incorporated preferentially in the interior of the Sc layers. At pB = 2 × 10-6 Torr, typically <3 at.% of N and <1.5 at.% of O was found, which did not influence the amorphous nanostructure of the layers. Multilayers deposited with a high pB ~2 × 10-5 Torr, a N content as high as ~37 at.% was measured by elastic recoil detection analysis. These multilayers mainly consist of understoichiometric face-centered cubic CrN x /ScN y nanocrystalline layers, which could be grown as thin at 0.3 nm and is explained by a stabilizing effect on the ScN y layers during growth. It is also shown that by adding a background pressure of as little as 5 × 10-6 Torr of pure N2 the soft x-ray reflectivity (? = 3.11 nm) can be enhanced by more than 100% by N incorporation into the multilayer structures, whereas pure O2 at the same background pressure had no effect.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-13063 (URN)10.1557/JMR.2009.0004 (DOI)
Available from: 2008-05-06 Created: 2008-05-06 Last updated: 2017-12-13
Mikhaylushkin, A., Abrikosov, I., Belonoshko, A. B., Johansson, B. & Simak , S. (2009). Instability of the body-centered tetragonal phase of iron under extreme conditions. PHYSICAL REVIEW B, 79(13), 132106-
Open this publication in new window or tab >>Instability of the body-centered tetragonal phase of iron under extreme conditions
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2009 (English)In: PHYSICAL REVIEW B, ISSN 1098-0121 , Vol. 79, no 13, p. 132106-Article in journal (Refereed) Published
Abstract [en]

The influence of the tetragonal and orthorhombic axial distortions on the body-centered cubic (bcc) phase of Fe at extreme conditions has been studied by means of first-principles calculations. We unambigiously demonstrate that the energy minimum corresponding to the body-centered tetragonal (bct) (c/a approximate to 0.9) structure, previously found in Fe upon the axial tetragonal distortion of the bcc phase along the Bains path under compression at zero temperature, is an artifact of the structural constraint. When the bcc structure is examined using the orthorhombic distortion involving the tetragonal distortion as a particular case, the bct (c/a approximate to 0.9) structural framework represents a saddle point between two mirrored face-centered cubic minima rather than a local minimum. Therefore we conclude that there is no ground to emphasize on possible thermal stabilization of the bct structure with a particular c/a ratio apart from the whole family of structures obtained by tetragonal, orthorhombic, or another type of axial distortions.

Keyword
ab initio calculations, crystal structure, high-pressure solid-state phase transformations, iron, thermal stability
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-18544 (URN)10.1103/PhysRevB.79.132106 (DOI)
Available from: 2009-06-01 Created: 2009-06-01 Last updated: 2009-06-01
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