Research by Salem Wright

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Toward strain control of magnetism in few-layer CrI3

Student: Salem C. Wright

Undergrad. School / Major: Presbyterian College / Physics

Faculty Advisor: Dr. Hugh Churchill (PHYS)

Research Area(s):

Nanoscience & Engineering

Microelectronics

Background/Relevance
  • The discovery of graphene ignited research into atomically thin materials, which can be manipulated to create new quantum devices dependent on the thickness of the materials
  • CrI3 is a known monolayer ferromagnet that can be cleaved into atomically thin layers for use in quantum devices
  • It is predicted that biaxial compressive strain of CrI3 will result in the formation of a quantum spin liquid, which is useful for quantum computing

Innovation
  • Biaxial strain of few-layer CrI3 will be used to tune its Curie temperature

Approach
  • Create a polypropylene substrate with a speckle pattern using electron beam lithography
  • Exfoliate thin flakes of CrI3 onto a silicon substrate
  • Use optical contrast techniques to measure the thickness of exfoliated layers
  • Transfer few-layer CrI3 onto a polypropylene substrate to apply compressive biaxial strain
  • Future work will use an optical cryostat to measure the Kerr rotation of few-layer CrI3 to determine the Curie temperature

Key Results
  • The thickness of few-layer CrI3 flakes was measured using optical contrast
  • Biaxial strain of polypropylene substrates was measured using digital image correlation

Conclusions
  • The thickness of few-layer CrI3 can be measured using optical contrast
  • The biaxial strain of polypropylene can be quantified using digital image correlation
    • CrI3 flakes can be transferred from a silicon substrate onto a polypropylene substrate for compressive biaxial strain

We would like to acknowledge Arash Fereidouni, Dr. Hugh Churchill, Dr. Jin Hu, Dr. Laurent Bellaiche, and Dr. Changsong Xu for their efforts on this project. Research Funded by National Science Foundation REU Grant # EEC-1757979 REU Site: Tomorrow’s Nanomanufacturing: Engineering with Science (TNEWS)