I am an Assistant Research Engineer at the
Materials Science and
Engineering Department, UCLA.
My current work includes first principles studies of structure-related
properties of several important classes of materials,
as well as development of novel methods for theoretical materials design.
My research couples highly-accurate
first-principles calculations to other tools (such as cluster-expansion-based
Monte Carlo) allowing to cover the vast phase space of possible atomic
configurations, allowing one to predict the properties of real materials.
In particular, I have been recently looking at the
structure and hydrogen diffusion in hydrogen storage materials
[17],
atomic structure of telluride thermoelectric materials
[18,19], and
on the atomic structure of f-element oxides and of superconducting alloys.
My earlier work at the National Renewable
Energy Lab focused on
furthering the development of cluster expansion (MBCE) approach and its application
to prediction of structural and ordering properties of
Au-Pd [13], GaAs-MnAs [11], and
Fe-(Ni,Pd,Pt) [manuscripts in preparation] alloys, as well as to
the first-principles studies of ferromagnetism in (Ga,Mn)As [14,
15]. I also developed Heisenberg Monte Carlo code for
systems with far-spanning magnetic interactions
used to obtain Curie temperatures for specific (Ga,Mn)As structures.
Finally, using percolation theory combined with
first-principles calculations, my collaborators and I have studied
possibile onset of vacancy-driven ferromagnetism in otherwise
nonmagnetic oxides [12,16].
Befor finishin my graduate studies, I performed first-principles studies
of then-recently discovered 40K superconductor
MgB2.
Using ab initio simulations,
I studied the superstructures observed in
Mg1-xAlxB2, and
explained the phase instabilities observed in this doped compound
[6] (previously, those instabilities had been deemed
to contradict ab initio results). We also showed that the infrared
absorption spectra appear to support the multiple
gap model proposed for the superconductivity in MgB2
[7].
I also studied the effects of inhomogeneities and phase fluctuations on
the electrical conductivity of high-Tc
superconductors and Josephson-junctions arrays
[2,8].
Another area of my research has been the properties of
composite and granular materials;
in particular the effective nonlinear properties of polycrystalline media
[1], Hall-induced magnetoresistance
(in composites [3]
and ferromagnets [4]),
and properties of partially disordered composite systems
[9].
Similar methods can be used to model the effect
of nonmagnetic impurities in high-Tc
materials [5].
For more details, please take a look at my CV (click here).
Publications
1.
S. Barabash and D. Stroud,
"Spectral Representation for the Effective Macroscopic Response of
a Polycrystal: Application to Third-Order Nonlinear Susceptibility,"
J. Phys.: Condens. Matter 11, 10323 (1999) .
(abstract / preprint)
(unzipped ps)
2.
S. Barabash, D. Stroud and I.-J. Hwang,
"Conductivity Due to Classical Phase Fluctuations in a
Model For High-T_c Superconductors,"
Phys. Rev. B 61, R14924 (2000) .
(abstract / preprint)
(unzipped ps)
3. Sergey V. Barabash, David J. Bergman, and D. Stroud,
"Magnetoresistance of Three-Constituent Composites: Percolation
Near a Critical Line,"
Phys. Rev. B 64, 174419 (2001) .
(abstract / preprint)
(unzipped ps)
4. Sergey V. Barabash, D. Stroud,
"Negative Magnetoresistance Produced by Hall Fluctuations in a
Ferromagnetic Domain Structure,"
Appl. Phys. Lett. 79, 979 (2001).
(abstract / preprint)
(unzipped ps)
5. Jeng-Da Chai, Sergey V. Barabash and D. Stroud,
"Simple Model for the Variation of Superfluid Density with Zn
Concentration in YBa2Cu3O7-x,"
Physica C 366, 13 (2001).
(abstract / preprint)
(unzipped ps)
6. Sergey V. Barabash and David Stroud,
"Structural and Superconducting Transitions in
Mg1-xAlxB2,"
Phys. Rev. B 66, 012509 (2002).
(abstract / preprint)
(unzipped ps)
7. Sergey V. Barabash and David Stroud,
"Transition Spectra for a BCS Superconductor with Multiple Gaps:
Model Calculations for MgB2,"
Phys. Rev. B 66,172501 (2002).
(abstract / preprint)
(unzipped ps)
8. Sergey V. Barabash and David Stroud,
"Superfluid Inhomogeneity and Microwave Absorption in Model High-Tc
Superconductors,"
Physica B 338, 224 (2003).
(abstract / preprint)
(unzipped ps)
9. Sergey V. Barabash and David Stroud,
"Effective Macroscopic Response of a Composite with Small Deviations
from Periodicity: Application to Colloidal Crystals,"
Physica B 338 , 4 (2003).
(abstract / preprint)
(unzipped ps)
10. Sergey V. Barabash and David Stroud,
"Models for Enhanced Absorption in Inhomogeneous Superconductors,"
Phys. Rev. B 67, 144506 (2003).
(abstract / preprint)
(unzipped ps)
11. Jorge Osorio-Guillen, Yu-Jun Zhao, Sergey V. Barabash, Alex Zunger,
"Structural stability of (Ga,Mn)As from
first-principles: Random alloys, ordered compounds, and
superlattices",
Phys.Rev. B 74, 035305 (2006).
12. J. Osorio-Guillen, S. Lany, S.V. Barabash, A. Zunger,
"Magnetism without magnetic ions: Percolation, exchange, and formation
energies of magnetism-promoting intrinsic defects in CaO",
Phys.Rev.Lett.
96, 107203 (2006).
13. Sergey V. Barabash, Volker Blum, Stefan Müller, Alex Zunger,
"Prediction of unusual stable ordered structures of Au-Pd alloys
via a first-principles cluster expansion",
Phys.Rev. B 74, 035108 (2006).
14. A. Franceschetti, S.V. Dudiy, S.V. Barabash, A. Zunger, J. Xu, and M. van
Schilfgaarde,
"First-Principles Combinatorial
Design of Transition Temperatures in Multicomponent Systems:
The Case of Mn in GaAs",
Phys.Rev.Lett.
97, 047202 (2006).
15. A. Franceschetti, S.V. Barabash, J. Osorio-Guillen A. Zunger, and M. van
Schilfgaarde,
"Enhancement of interactions between magnetic ions in
semiconductors due to declustering",
Phys.Rev. B 74, 241303(R) (2006).
16. J. Osorio-Guillen, S. Lany, S. V. Barabash, and A. Zunger
"Nonstoichiometry as a source of magnetism in otherwise nonmagnetic oxides:
Magnetically interacting cation vacancies and their percolation",
Phys. Rev. B 75, 184421 (2007).
17. Hakan Gunaydin, Sergey V. Barabash, K. N. Houk, and V. Ozolins,
"First-Principles Theory of Hydrogen Diffusion in Aluminum",
Phys. Rev. Lett. 101, 075901 (2008).
18. S. V. Barabash, V. Ozolins, and C. Wolverton,
"First-Principles Theory of Competing Order Types, Phase Separation, and
Phonon Spectra in Thermoelectric AgPbmSbTem+2 Alloys",
Phys. Rev. Lett. 101, 155704 (2008) .
19. S. V. Barabash, V. Ozolins, and C. Wolverton,
"First principles theory of the coherency strain, defect energetics, and
solvus boundaries in the PbTe-AgSbTe2 system",
Phys. Rev.B 78, 214109 (2008) .
My General Exam paper:
Superconductivity in MgB2
My Ph.D. Thesis:
Topics in the Physics of Inhomogeneous Materials
(pdf)
Talks, preprints etc.: my CV.
Last modified: May 2007.