Dr. Robert Green BE, BSc, PhD

Current Affiliation

• Assistant Professor, University of Saskatchewan

Ph.D. Thesis

• Transition Metal Impurities in Semiconductors: Induced Magnetism and Band Gap Engineering (link)

Research Projects

Material Science

My current work focuses on the field of spintronics, where conventional electronics are given an extra layer of dimensionality by adding control over the spin property of electrons. In particular, I am studying dilute magnetic semiconductors (DMS), where a traditional, non-magnetic semiconductor is doped with magnetic atoms to induce magnetism and therefore spin transport properties. These magnetic atoms are usually transition metals, which means these materials are ideal candidates for study with soft x-ray spectroscopy. By using X-ray Absorption Spectroscopy and X-ray Emission Spectroscopy, we can probe the local environment of the magnetic atoms to determine how they interact with the host material to induce magnetic effects.

Instrumentation

I have also been involved with the design and construction of the new inelastic scattering endstation on the REIXS beamline at the Canadian Light Source. A few of my contributions are the design of permanent magnet arrays that will be used for magnetic dichroism experiments, helping with the redesign of a preamplifier for the x-ray detector so it can meet the special constraints of its location, and assembling a mobile sample preparation chamber. I am currently assisting with the final assembly and commissioning of the endstation.

Awards

• Saskatchewan Innovation and Opportunity Scholarship (Apr. 2012)
• Canadian Light Source AUM Student Poster Award (Jun. 2011)
• Advanced Light Source AUM Student Poster Award (Oct. 2010)
• NSERC Postgraduate Scholarship, D3 (Sept. 2010)
• NSERC Canada Graduate Scholarship, M (Sept. 2009)
• U of S PEP Most Distinguished Graduate (May 2009)
• NSERC Undergraduate Student Research Award (May 2009)
• NSERC Undergraduate Student Research Award (May 2007)

Publications

1. Transition from Reconstruction toward Thin Film on the (110) Surface of Strontium Titanate
   Z. Wang, A. Loon, A. Subramanian, S. Gerhold, E. McDermott, J.A. Enterkin, M. Hieckel, B.C. Russell, R.J. Green, A. Moewes, J. Guo, P. Blaha, M.R. Castell, U. Diebold, and L.D. Marks, Nano Letters) 16, 2407-2412 (2016).
2. Adjacent Fe-Vacancy Interactions as the Origin of Room Temperature Ferromagnetism in (In_1-xFe_x)₂O₃ 
   R.J. Green, T.Z. Regier, B. Leedahl, J.A. McLeod, X.H. Xu, G.S. Chang, E.Z. Kurmaev, and A. Moewes, Phys. Rev. Lett. 115, 167401 (2015).
3. Study of the Structural Characteristics of 3d metals Cr, Mn, Fe, Co, Ni, and Cu Implanted in ZnO and TiO₂ – Experiment and Theory
   B. Leedahl, D.Z. Zatsepin, D.W. Boukhvalov, E.Z. Kurmaev, R.J. Green, I.S. Zhidkov, S.S. Kim, N.V. Gavrilov, S.O. Cholak, and A. Moewes, J. Phys. Chem. C 118, 28143-28151 (2014).
4. Electronic structure and spin trapping in LiMnAs and LiFeAs:Mn
   J.A. McLeod, E.Z. Kurmaev, I. Perez, R.J. Green, L.Y. Xing, X.C. Wang, C.-Q. Jin, and A. Moewes, J. Phys. Cond. Matt. 27, 015504 (2015).
5. Electronic Structure of FeSe_1-xTe_x Studied by X-ray Spectroscopy and Density Functional Theory
   I. Pérez, J.A. McLeod, R.J. Green, R. Escamilla, V. Ortiz, and A. Moewes, J. Phys. Chem. C 118, 25150-25157 (2014).
6. Electronic structure of Co-substituted FeSe superconductor probed by soft X-ray spectroscopy and density functional theory 
   I. Perez, J.A. McLeod, R.J. Green, R. Escamilla, V. Ortiz, and A. Moewes, Phys. Rev. B 90, 014510 (2014).
7. Measuring Partial Fluorescence Yield using Filtered Detectors
   T.D. Boyko, R.J. Green, A. Moewes, T.Z. Regier, J. Synchr. Rad. 21, 716-721 (2014).
8. Comment on “State-Dependent Electron Delocalization Dynamics at the Solute-Solvent Interface: Soft X-ray Absorption Spectroscopy and Ab Initio Calculations”
   R.J. Green, D. Peak, A.J. Achkar, J.S. Tse, A. Moewes, D.G. Hawthorn, and T.Z. Regier, Phys. Rev. Lett. 112, 129301-1-2 (2014).
9. Local Structure of Fe Impurity Atoms in ZnO: Bulk versus Surface
   J.A. McLeod, D.W. Boukhvalov, D.Z. Zatsepin, R.J. Green, B. Leedahl, L. Chui, E.Z. Kurmaev, I.S. Zhidkov, L.D. Finkelstein, N.V. Gavrilov, S.O. Cholakh, and A. Moewes, J. Phys. Chem. C 118, 5336-5345 (2014).
10. Electronic Band gap reduction and intense luminescence in Co and Mn ion-implanted SiO₂
    R.J. Green, D.A. Zatsepin, D.J. St. Onge, E.Z. Kurmaev, N.V. Gavrilov, and A. Moewes, J. Appl. Phys. 115, 103708-1-7 (2014).
11. Structural defects induced by Fe-ion implantation in TiO₂
    B. Leedahl, D.A. Zatsepin, D.W. Boukhvalov, R.J. Green, J.A. McLeod, S.S. Kim, E.Z. Kurmaev, I.S. Zhidkov, N.V. Gavrilov, S.O. Cholakh, and A. Moewes, J. Appl. Physics 115, 053711-1-7 (2014).
12. Electronic band gap reduction in Manganese Carbodiimide: MnNCN
    T.D. Boyko, R.J. Green, R. Dronskowski, and A. Moewes, J. Phys. Chem. C 117, 12754-12761 (2013).
13. Band gap tuning in ZnO Through Ni doping via spray pyrolysis
    S.C. Das, R.J. Green, J. Podder, G.S. Chang, and A. Moewes, J. Phys. Chem. C 117, 12745-12753 (2013).
14. The formation of Ti-O tetrahedra and band gap reduction in SiO₂ via pulsed ion implantation   
    R.J. Green, D.A. Zatsepin, A. Hunt, E.Z. Kurmaev, N.V. Gavrilov, and A. Moewes, J. Appl. Physics 113, 103704-1-4 (2013).
15. Interplay of ballistic and chemical effects in the formation of structural defects for Sn and Pb implanted silica  
    R.J. Green, A. Hunt, D.A. Zatsepin, D.W. Boukhvalov, J.A. McLeod, E.Z. Kurmaev, N.A. Skorikov, N.V. Gavrilov, and A. Moewes, J. Non-Cryst. Solids 358, 3187-3192 (2012).
16. Room Temperature Ferromagnetism via unpaired dopant electrons and p–p coupling in carbon-doped In₂O₃: Experiment and Theory
    R.J. Green, D.W. Boukhvalov, E.Z. Kurmaev, L.D. Finkelstein, H.W. Ho, K.B. Ruan, L. Wang, and A. Moewes, Phys. Rev. B 86, 115212-1-8 (2012).
17. Band gap Engineering in TiO₂-based Ternary Oxides
    J.A. McLeod, R.J. Green, E.Z. Kurmaev, N. Kumada, A.A. Belik, and A. Moewes, Phys. Rev. B 85 195201-1-8 (2012).
18. Effect of 3d-doping on the electronic structure of BaFe₂As₂  
    J.A. McLeod, A. Buling, R.J. Green, T.D. Boyko, N.A. Skorikov, E.Z. Kurmaev, M. Neumann, L.D. Finkelstein, N. Ni, A. Thaler, S.L. Bud’ko, P.C. Canfield, and A. Moewes, J. Phys.: Cond. Matt. 24, 215501-1-11 (2012).
19. Structural and band gap investigation of GaN:ZnO heterojunction solid solution photocatalyst probed by soft X-ray spectroscopy
    E.J. McDermott, E.Z. Kurmaev, T.D. Boyko, L.D. Finkelstein, R.J. Green, K. Maeda, K. Domen, and A. Moewes, J. Phys. Chem. C 116, 7694-7700 (2012).
20. Structural ordering in a silica glass matrix under Mn ion implantation
    D.A. Zatsepin, R.J. Green, A. Hunt, E.Z. Kurmaev, N.V. Gavrilov, and A. Moewes, J. Phys.: Cond. Matt. 24, 185402-1-7 (2012).
21. Identifying Local Dopant Structures and their Impact on Magnetic Properties in Spintronic Materials
    R.J. Green, G.S. Chang, X.Y. Zhang, A. Dinia, E.Z. Kurmaev, and A. Moewes, Phys. Rev. B 83, 115207-1-6 (2011).
22. Valence Structure of Alkaline and Post-Transition Metal Oxides
    J.A. McLeod, R.J. Green, N.A. Skorikov, L.D. Finkelstein, M. Abu-Samak, E.Z. Kurmaev, and A. Moewes, Oxide-based Materials and Devices II  Book Series: Proceedings of SPIE 7940, 79400R (2011).
23. Appearance of Ferromagnetism in Co-Doped CeO₂ Diluted Magnetic Semiconductors Prepared by Solid State Reaction
    A. Bouaine, R.J. Green, S. Colis, P. Bazylewski, G.S. Chang, A. Moewes, E.Z. Kurmaev, and A. Dinia, Journal of Physical Chemistry C 115, 1566-1560 (2011).