Dr. Saicharan Aswartham

  • Postdoctoral Research Scientist
CP354C, CP156
859-257-9169, 8592181297
Research Interests:
Education

Ph.D. in Physics from IFW-Dresden (TU-Dresden), 2012, Germany.

Biography
Mar '14 - Present: Post-doctoral fellow, University of kentucky, Lexington, USA
Nov '12 - Mar '14: Post-doctoral fellow, IFW Dresden, Germany.
Aug '09 - Nov '12: Ph.D in Physics from IFW-Dresden, Germany.
Feb '09 - Aug '09: Guest scientist in IFW-Dresden, Germany.
 
Awards/Prize
 
Young scientist prize from German Crystal Growth Socienty (DGKK) 
DGKK-Nachwuchsforscherpreises 2014
Research

Single crystal growth

Synthesis and characterization of novel materials

Superconducting and magnetic materials

Selected Publications: 

2015

31) Evolution of magnetism in single-crystal Ca2Ru1-xIrxO4S. J. Yuan, J. TerzicJ. C. Wang, L. Li, S. Aswartham, Feng. Ye, W. H. Song, and G. Cao. Phys. Rev. B. 92, 024425, (2015).

30) Charge-order dictated magnetic order in dimer chain Iridate Ba5AlIr2O11: J. TerzicJ. C. Wang, Feng. Ye, W. H. Song, S. J. Yuan, S. AswarthamR. K. Kaul, L. E. Delong and G. Cao. Phys. Rev. B. 91, 235147, (2015).

29) Crystal growth and electronic phase diagram of 4d doped Na1-xFe1-xRhxAs in comparision with 3d  Na1-xFe1-xCoxAsF. SteckelM. Maroslova, R. Beck, I. Morozov, S. Aswartham, D.V. Evtushinsky, Christian. G-F Blum, M. Abdel-Hafiez, D. Bomber, J. Maletz, S. Borisenko, Andrei V. Shevelkov, A.U.B. Wolter-Giraud, C. Hess, S. Wurmehl, and B. Büchner. Phys. Rev. B 91, 184516, (2015).

28) Spin reorientation in Ba0.65Na0.35Fe2As2: stuided by single-crystal neutron diffraction: F. Wasser, A. Schneidewind, Y. Sidis, S. Wurmehl, S. Aswartham, B. Büchner, and M. Braden. Phys. Rev. B 91, 060505(R) (2015)

2014

27) Lattice-tuned magnetism of Ru4+(4d4) ions in single crystals of the layered honeycomb ruthenates Li2RuO3 and Na2RuO3: J. C. Wang, J. Terzic, T. F. Qi, Feng. Ye, S. J. Yuan, S. Aswartham, S. V. Streltsov, D. I. Khomskii, R. K. Kaul. and G. Cao. Phys. Rev. B. 90, 161110(R), (2014).

26) Identical spin fluctuations in Cu and Co doped BaFeAs  independent of electron doping: H.-J. Grafe, U. Graefe, A. P. Dioguardi, N. J. CurroS. Aswartham, S. Wurmehl, B. Büchner. Phys. Rev. B. 90, 094519, (2014).

25) Josephson effect and Andreev reflection in Ba1-xNaxFeAs (x= 0.25 and 0.35) point contacts: V. V. Fisun, O. P. Balkashin, O.E. Kvitnitskaya, I. A. Korovkin,  N. V. GamayunovaS. Aswartham, S. Wurmehl, Yu. G. Naidyuk. Fizika Nizkikh Temperatur. 40, 1175, (2014).

24) Superconducting properties of K1-xNaxFe2As2  under pressure: V. Grinenko, W. Schottenhamel, A.U.B. Wolter, D. V. Efremov, S.-L. Drechsler, S. Aswartham, M. Kumar, S. Wurmehl, M. Maroslova, I. Morozov, B. Holzapfel, B. Büchner, E. Ahrens, S. I. Troyanov, S. Koehler, E. Gati, S. Knoener, N. H. Hoang, M. Lang, F. Ricci, G. Profeta. Phys. Rev. B. 90, 094511, (2014). 

23) Single 20mev boson  mobe in KFe2As2 detected by point contact spectroscopy: Yu. G. Naidyuk, O.E. Kvitnitskaya, N. V. Gamayunova, L. Boeri, S. Aswartham, S. Wurmehl, B. Büchner, D. V. Efremov, G. Fuchs, S.-L. Drechsler. Phys. Rev. B. 90, 094505, (2014). 

22) Specific Heat of K1-xNaxFe2As2 at very low temperatures: A. Reifenberger, M. Hempel, P. Vogt, S. Aswartham, M. Abdel-Hafiez, V. Grinenko, S. Wurmehl, S.-L. Drechsler, A. Fleischmann, C. Enss, R. Klingeler. Jorurnal of Low Temperature Physics, 175, 5-6, (2014).

21) Exploring point contact spectra of Ba1-xNaxFe2As2 in normal and superconducting states: Yu. G. Naidyuk, O.E. Kvitnitskaya, S. Aswartham, S. Wurmehl, G. Fuchs, K. Nenkov, B. BüchnerPhys. Rev. B. 89, 140512, (2014). 

20) Strong pairing at iron 3dxz;yz orbital’s in hole-doped BaFe2As2: D. V. Evtushinsky, V. B. Zabolotnyy, T. K. Kim, A. A. Kordyuk, A. N. Yaresko, J. Maletz, S. Aswartham, S. Wurmehl, A. V. Boris, D. L. Sun, C. T. Lin, H. Q. Luo, Z. S. Wang, H. H. Wen, A. Varykhalov, R. Follath, B. Büchner, and  S. V. Borisenko. Phys. Rev. B. 89, 060514, (2014).

19) Superconducting specific heat jump ΔC αTcβ (β=2) K1-xNaxFe2As2 : V. Grinenko, S.-L. Drechsler, D. Efremov, S. Aswartham, D. Gruner, M. Maroslova, I. Morozov, K. Nenkov, A.U.B. Wolter-Giraud, S. Wurmehl, B. Holzapfel, and B. Büchner. Phys. Rev. B. 89, 060504(R), (2014).

2013

18) Diversity of microstructural phenomena in superconducting and non-superconducting RbxFe2-ySe2: A TEM study at the atomic scale: Maria V. Roslova, Oleg I. Lebedev, Igor V. Morozov, Saicharan Aswartham, Andrei V. Shevelkov, Sabine Wurmehl, and Bernd Büchner. Inorganic Chemistry. (2013).

17) Evidence for a vortex-glass transition in superconducting Ba(Fe0.9Co0.1)2As2: G. Prando, R. Giraud, S. Aswartham, M. Abdel-Hafiez,  A. U. B. Wolter, S. Wurmehl, and B. Büchner. J. Phys. Condens. Matter, 25, 505701, (2013)

16) Flux dynamics and avalanches in 122 pnictide superconductor Ba0.65Na0.35Fe2As2single crystals: A. K. Pramanik, S. Aswartham, A. U. B. Wolter, S. Wurmehl, V. Kataev, and B. Büchner. J. Phys. Condens. Matter, 25, 495701 (2013)

15) Evidence of d-wave superconductivity in K1-xNaxFe2As2 (x = 0 and 0.1) single crystals from Low-T Specific Heat: M. Abdel-Hafiez, S. Aswartham, V. Grinenko, I. Morozov, M. Maroslova, O. Vakaliuk, S.-L. Drechsler, S. Johnston , C. Hess, S. Wurmehl, A.U.B. Wolter, B. Büchner, E. L. Green, J. Wosnitza, P. Vogt, A. Reifenberger, and R. Klingeler. Phys. Rev. B. 87, 180507(R), (2013)

14) Observation of charge accumulation and onsite Coulomb repulsion at transition metal impurities in the iron pnictides:     R. Kraus, V. Bisogni, L. Harnagea, S. Aswartham, S. Wurmehl, B. Büchner, and J. Geck G. Levy, I. Elfimov, and G.A. Sawatzky. Phys. Rev. B. 87, 134516, (2013)

13) Intrinsic pinning and the critical current scaling of clean epitaxial Fe(Se,Te) thin films: K. Iida, J. Hänisch, E. Reich, F. Kurth, R. Hühne, L. Schultz, B. Holzapfel, A. Ichinose, M. Hanawa, I. Tsukada, M. Schulze,  S. Aswartham, S. Wurmehl, and B. Büchner. Phys. Rev. B.87, 104510, (2013)

12) Electronic band structure and momentum dependence of the superconducting gap in (Ca, Na)Fe2As2 from angle-resolved photoemission spectroscopy: D. V. Evtushinsky, V. B. Zabolotnyy, L. Harnagea, A. N. Yaresko, S. Thirupathaiah, A. A. Kordyuk, J. Maletz, S. Aswartham, S. Wurmehl, E. Rienks, R. Follath, B. Büchner, S. V. Borisenko. Phys. Rev. B. 87, 094501, (2013)

2012

11) Strong Competetion of Superconducting and Magnetic Order Paramenter in Ba1-xNaxFe2As2 : Hemke Maeter, Gwendolyne Pascua, Hubertus Luetkens, Johannes Knolle, Saicharan Aswartham, Sabine Wurmehl, Günter Behr, Bernd Büchner, Zurab Shermadini, Kamil Sedlak, Alex Amato, Roderich Moessner, Ilya Eremin, Hans-Henning Klauss. arXiv:1210.6881, (2012)

10) Hole-doping in BaFe2As2: The case of Ba1-xNaxFe2As2 single crystals: S.  Aswartham, M. Abdel-Hafiez, M. Kumar, G. Behr,  D. Bombor, V. B. Zabolotnyy, A. A. Kordyuk, T. K. Kim, D. V. Evtushinsky, S. V. Borisenko, C. Hess, A.U.B. Wolter , S. Wurmehl and B. Büchner. Phys. Rev. B. 85, 224520, (2012)

9) Local magnetic anisotropy in BaFe2As2: A polarized inelastic neutron scattering study: N. Qureshi, P. Steffens, S. Wurmehl, S. Aswartham, B. Büchner, and M. Braden. Phys. Rev. B 86, 060410(R) (2012)

8) Specific heat and upper critical fields in KFe2As2 single crystals: M. Abdel-Hafiez, S. Aswartham, S. Wurmehl, V. Grinenko, C. Hess, S.-L. Drechsler, S. Johnston, A.U.B. Wolter, B. Büchner, H. Rosner, L. Boeri. Phys. Rev. B 85, 134533 (2012) 

7) 75As NMR-NQR study in superconducting LiFeAs: S.-H. Baek, H.-J. Grafe, F. Hammerath, M. Fuchs, C. Rudisch, L. Harnagea, S. Aswartham, S. Wurmehl, J. van den Brink, B. Büchner. Europ. Phys. J. B 85 159 (2012)

6) Disordered magnetism in KFe2As2 single crystals: V. Grinenko, S.-L. Drechsler, M. Abdel-Hafiez, S. Aswartham, A.U.B. Wolter-Giraud, S. Wurmehl, C. Hess, K. Nenkov, G. Fuchs, D. Efremov, B. Holzapfel, J. Van den Brink and B. Büchner. Phys. Stat. Sol. (b), pssc.201200805.R1 (2012)

2011

5) Single crystal growth and physical properties of superconducting ferro-pnictides Ba(Fe,Co)2As2 grown using self-flux and Bridgman techniques: S. Aswartham, C. Nacke, G. Friemel, N. Leps, S. Wurmehl, N. Wizent, C. Hess, R. Klingeler, G. Behr, S. Singh, B. Büchner. J. Cryst. Growth 314 341 (2011)

4) Multigap superconductivity in single crystals of Ba0.65Na0.35Fe2As2: A calorimetric investigation A.K. Pramanik, M. Abdel-Hafiez, S. Aswartham, A.U.B. Wolter, S. Wurmehl, V. Kataev,B. Büchner. Phys. Rev. B, 84 64525 (2011) 

3) Suppressed superconductivity in charge-doped Li(Fe1-xCox)As single crystals: S. Aswartham, G. Behr, L. Harnagea, D. Bombor, A. Bachmann, I.V. Morozov,V.B. Zabolotnyy, A.A. Kordyuk, T.K. Kim, D.V. Evtushinsky, S.V. Borisenko, A.U.B. Wolter, C. Hess, S. Wurmehl, B. Büchner. Phys. Rev. B 84 54534 (2011) 

2) Generic Fe buffer layers for Fe-based superconductors: Epitaxial FeSe1-xTex thin films: K. Iida, J. Haenisch, M. Schulze, S. Aswartham, S. Wurmehl, B. Büchner, L. Schultz, B. Holzapfel. Appl. Phys. Lett. 99 202503 (2011) 

2010

1) Critical current and vortex dynamics in single crystals of Ca(Fe1-xCox)2As2  A.K. Pramanik, L. Harnagea, S. Singh, S. Aswartham, G. Behr, S. Wurmehl, C. Hess, R. Klingeler, B. Büchner. Phys. Rev. B 82 14503 (2010) 

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