Ankit Disa

Ankit Disa's picture
Postdoctoral Associate
AP: Applied Physics
Year: 
6
Address: 
15 Prospect St, New Haven, CT 06511
Office Location: 
Becton Center 301
Bio: 

I obtained my PhD in Applied Physics at Yale in 2016. I am currently a Postdoctoral Associate here in the lab of Prof. Charles Ahn. I came to Yale in 2010 after graduating with a B.S. in Applied & Engineering Physics and a minor in Computer Science from Cornell.

Along with a passion to know how things work (thus, the physics), I enjoy almost everything in life, including (but not limited to) tennis, karaoke, airports, experimental jazz, inline skating and “socializing”.

Research: 

Research Interests

Broadly, I am interested in understanding and controlling the properties of strongly correlated electron systems to study emergent quantum phenomena and design novel functionalities. Particular topics of interest include charge/spin/orbital order, high-temperature superconductivity, electronic/magnetic phase transitions, and topological states. I am especially interested in the development of such behavior at thin film interfaces and the ability to manipulate them using heterostructuring and ferroelectric field effects.

Current Research

- In the lab of Prof. Charles Ahn here at Yale, I have been studying nickel-based rare-earth perovskite oxides. The nickelates display behaviors of strongly correlated systems, exhibiting, for instance, a first-order phase transition to a low-temperature antiferromagnetic insulating phase that depends on the size of the rare-earth ion. I use molecular beam epitaxy to grow thin films of single-component and layered nickelates and characterize them using low temperature transport, SQUID magnetometry, and synchrotron-based x-ray spectroscopy and diffraction to determine the effects of dimensionality, carrier modulation, and interfacial coupling on the electronic and magnetic structure of this system (see Publications ([2-5,7-9]).

Here, I include the atomic structure of a three-component heterostructure that shows large orbital polarization due to charge transfer, symmetry-breaking, and polar distortions. The image compares the results from density functional calculations and synchrotron x-ray measurements of the experimentally-grown structure.

Past Research

- Strain in single-crystal oxides: At Cornell, working with Prof. Joel Brock, I studied the strain caused by oxygen vacancies on single crystal SrTiO3.  Using simulations from first-principles calculations and diffuse x-ray scattering at the Cornell High Energy Synchrotron Source, my group and I were able to determine that strain screening occurs due to mobile vacancies (see Publications [1,10]).  

A contour image of the diffuse scattering in this system that I calculated is shown below:

Publications: 

Articl​es

  1. Strain and oxygen vacancy ordering in SrTiO3: Diffuse x-ray scattering studies” Y. Kim, A.S. Disa, T.E. Babakol, X. Fang, J.D. Brock, Phys. Rev. 92, 064105 (2015)

  2. Research Update: Orbital polarization in LaNiO3-based heterostructures” A.S. Disa, F.J. Walker, S. Ismail-Beigi, C.H. Ahn, APL Mater3, 062303 (2015)

  3. Orbital Engineering in Symmetry-Breaking Polar Heterostructures” A.S. Disa, D.P. Kumah, A. Malashevich, H. Chen, D.A. Arena, E.D. Specht, S. Ismail-Beigi, F.J. Walker, C.H. Ahn, Phys. Rev. Lett114, 026801 (2015)
    * Editor’s Suggestion, highlighted in a Viewpoint in Physics, and selected as Editors’ Choice in Science
    * Coverage in Yale Engineering News

  4. Effect of Surface Termination on the Electronic Properties of LaNiO3 Films” D.P. Kumah, A. Malashevich, A.S. Disa, D.A. Arena, S. Ismail-Beigi, F.J. Walker, and C.H. Ahn, Phys. Rev. Applied2, 054004 (2014)

  5. Conduction at a Ferroelectric Interface” M.S.J. Marshall, A. Malashevich, A.S. Disa, M.-G. Han, H. Chen, Y. Zhu, S. Ismail-Beigi, F.J. Walker, and C.H. Ahn, Phys. Rev. Applied2, 051001 (2014)
    * Editor’s Suggestion

  6. Synthesis of SnTe Nanoplates with {100} and {111} Surfaces” J. Shen, Y. Jung, A.S. Disa, F.J. Walker, C.H. Ahn, J.J. Cha, Nano Lett14, 4183 (2014)

  7. Tuning the Structure of Nickelates to Achieve Two-Dimensional Electron Conduction” D.P. Kumah, A.S. Disa, J.H. Ngai, H. Chen, A. Malashevich, J.W. Reiner, S. Ismail-Beigi, F.J. Walker, C.H. Ahn, Adv. Mater26, 1935 (2014)

  8. Phase diagram of compressively strained nickelate thin films” A.S. Disa, D.P. Kumah, J.H. Ngai, E.D. Specht, D.A. Arena, F.J. Walker, C.H. Ahn, APL Mater1, 032110 (2013)

  9. Modifying the Electronic Orbitals of Nickelate Heterostructures via Structural Distortions” H. Chen, D. P. Kumah, A.S. Disa, F.J. Walker, C.H. Ahn, S. Ismail-Beigi, Phys. Rev. Lett110, 186402 (2013)

  10. Strain screening by mobile oxygen vacancies in SrTiO3” Y. Kim, A.S. Disa, T.E. Babakol, J. D. Brock, Appl. Phys. Lett. 96, 251901 (2010)
    * Featured on cover

Posters/Prese​ntations:

  1. “Widely Tunable Orbital Configurations in Oxides with Symmetry-Breaking Heterostructures”
    22nd International Workshop on Oxide Electronics, Poster, October 2015, Paris, France

  2. “Engineering orbital structure in correlated oxides with three-component superlattices”
    15th Int’l Conf. on Electronic Structure and Spectroscopy, Poster, September 2015, Stony Brook, NY

  3. “Control of structure, conduction, and orbital polarization in nickelate heterostructures”
    International Materials Research Congress, Presentation, July 2015, Cancun, Mexico

  4. “Manipulating Electronic Structure and Transport in Complex Oxide Heterostructures”
    YINQE Seminar, Yale University, April 2015, New Haven, CT

  5. “Orbital engineering of nickelates in three-component heterostructures”
    American Physical Society March Meeting, Presentation, March 2015, San Antonio, TX

  6. “Strain-induced renormalization of the thin film phase diagram of rare-earth nickelates”
    21st Workshop on Oxide Electronics, Poster, September 2014, Bolton Landing, NY

  7. “Renormalization of the nickelate phase diagram in strained thin films”
    American Physical Society March Meeting, Presentation, March 2014, Denver, CO

  8. “Achieving Orbital Polarization in Nickelate Heterostructures”
    Materials Research Society Fall Meeting, Presentation, December 2013, Boston, MA

  9. “Single-band Fermi surface engineering in nickelates”
    20th Workshop on Oxide Electronics, Presentation, September 2013, Singapore

  10. “Phase diagram of epitaxially strained nickelate thin films”
    CRISP Seminar, Yale University, August 2013, New Haven, CT

  11. “Two dimensional Mott physics in the rare earth nickelates”
    American Physical Society March Meeting, Presentation, March 2013, Baltimore, MD

  12. “2D conduction in rare-earth nickelates”
    Materials Research Society Fall Meeting, Presentation, November 2012, Boston, MA

  13. “Manipulating the nickelate metal-insulator transition through chemical doping”
    19th Workshop on Oxide Electronics, Poster, October 2012, Apeldoorn, Netherlands

  14. “Modifying the electronic structure of rare-earth nickelates”
    CRISP Seminar, Yale University, July 2012

  15. “Probing the Nickelate Ground State in NdNiO3 Superlattices”
    American Physical Society March Meeting, Presentation, March 2012, Boston, MA

  16. “Transport and Spectroscopy Studies of Ultrathin Doped Nickelate Films”
    American Physical Society March Meeting, Presentation, March 2011, Dallas, TX

  17. “Strain Screening by Mobile Oxygen Vacancies in Strontium Titanate”
    American Physical Society March Meeting, Presentation, March 2010, Portland, OR

  18. “Diffuse Scattering from Oxygen Vacancies in Strained Thin Films of SrTiO3”
    Cornell ELI Research Poster Session, Poster, April 2009, Ithaca, NY

  19. “Characterizing electrical transport properties of Co3O4 and CoFe2O4 epitaxial thin films”
    Leadership Alliance National Symposium, Presentation, July 2008, Hartford, CT