- Program Year: 4
- Academic Institution: Columbia University
- Field of Study: Micro/Nanoscale Engineering
- Academic Advisor: James Hone
Lawrence Livermore National Laboratory (2016)
M.S. Physics and General Science Education, Teachers College at Columbia University, 2010; B.A. Art Practice, and B.A. Physics, University of California, Berkeley, 2007
Summary of Research
Studying graphene and semiconducting transition metal dichalcogenides enables the development of nanoscale optical and electric circuits for flexible electronics, as well as the development of high-strength stretchy composites. Additionally, these two-dimensional (2D) materials present an opportunity to study materials under extreme conditions at the quantum and continuum scale simultaneously. My research is focused on probing extreme strain in these materials, as well as characterizing the physics of relevant 2D material heterostructure devices.
For studying stress and strain, 2D materials can be experimentally loaded using an AFM up to their theoretical maximum elastic strains (near 25%) while reading out the force vs. displacement. In this way, a stress-strain relation for a known geometry (e.g. a point load applied to the center of a circular membrane) can be obtained with cyclic loading up to fracture. This is how it was shown in 2008 that graphene is 100 times stronger than steel, making it the strongest material in the world. Since then this technique has been used successfully to show that the strength of polycrystalline (CVD) graphene is still close to the intrinsic strength of graphene, and to demonstrate a piezoelectric effect in molybdenum disulfide. This experimental platform provides a method for inducing a known strain which can then be correlated with other effects.
We plan to use a robust experimental platform that includes photocurrent measurement, Raman spectroscopy, the atomic force probe microscopy setup described above, and electrical measurement both in and out of an airless and waterless glovebox system in order to probe strain-related effects. Challenges include the tendency for thin films to slip on the substrate under load, the fact that currently the material must be suspended, and compatibility of the systems named for simultaneous measurement. Currently I am focusing on fabrication procedures and developing experimental apparatuses related to the work.
Tunable crystal symmetry in graphene-boron nitride heterostructures with coexisting moire superlattices. Nathan R. Finney, Matthew Yankowitz, Lithurshanaa Muraleetharan, K. Watanabe, T. Taniguchi, Cory R. Dean, James Hone. arXiv:1903.11191 (2019), in review
An ultrafast symmetry switch in a Weyl semimetal. Edbert J. Sie, Clara M. Nyby, C. D. Pemmaraju, Su Ji Park, Xiaozhe Shen, Jie Yang, Matthias C. Hoffmann, B. K. Ofori-Okai, Renkai Li, Alexander H. Reid, Stephen Weathersby, Ehren Mannebach, Nathan Finney, Daniel Rhodes, Daniel Chenet, Abhinandan Antony, Luis Balicas, James Hone, Thomas P. Devereaux, Tony F. Heinz, Xijie Wang & Aaron M. Lindenberg. Nature volume 565, pages 61-66 (2019).
Engineering the structural and electronic phases of MoTe2 through W substitution. D. Rhodes, D.A. Chenet, B.E. Janicek, C. Nyby, Y. Lin, W. Jin, D. Edelberg, E. Mannebach, N. Finney, A. Antony, T. Schiros, T. Klarr, A. Mazzoni, M. Chin, Y. Chiu, W. Zheng, Q.R. Zhang, F. Ernst, J.I. Dadap, X. Tong, J. Ma, R. Lou, S. Wang, T. Qian, H. Ding, R.M. Osgood Jr, D.W. Paley, A.M. Lindenberg, P.Y. Huang, A.N. Pasupathy, M. Dubey, J. Hone, L. Balicas. American Chemical Society Nano Letters, February 2017, 17 (3), pp. 1616-1622
Design, Fabrication, and Test of a Superconducting Dipole Magnet Based on Tilted Solenoids. S. Caspi, D.R. Dietderich, P. Ferracin, N.R. Finney, M.J. Fuery, S.A. Gourlay, A.R. Hafalia. IEEE Transactions on Applied Superconductivity Volume 17, Issue 2, June 2007 Page(s): 2266-2269
Distinction in General Scholarship (upon conferral of B.A.), University of California Berkeley, Dec. 2007
Highest Honors (upon conferral of A.A.), Santa Rosa Junior College, May 2005