University of Illinois Urbana-Champaign

Beyond the isotropic two-dimensional Heisenberg model: Raman scattering studies of the transition between isotropic and anisotropic spin dynamics in Sr2IrO4

Gim, Yewon

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https://hdl.handle.net/2142/101467

Description

Title
Beyond the isotropic two-dimensional Heisenberg model: Raman scattering studies of the transition between isotropic and anisotropic spin dynamics in Sr2IrO4
Author(s)
Gim, Yewon
Issue Date
2018-05-21
Director of Research (if dissertation) or Advisor (if thesis)
Cooper, Lance
Doctoral Committee Chair(s)
MacDougall, Greg
Committee Member(s)
  • Vishveshwara, Smitha
  • Lorenz, Virginia
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • iridate
  • raman scattering
  • strong spin-orbit coupling
Abstract
With discovery of novel superconductivity in Sr2RuO4 and the exciting theoretical results regarding strong spin-orbit couple regime, iridate compounds have come to a focus in many experimental and theoretical studies. Especially, Sr2IrO4 has come to special interest due to 3-d parent compoun La2CuO4. Understanding the similarity and difference in the two compounds are crucial toward search for novel superconductivity in Sr2IrO4 compounds. In this thesis we present inelastic scattering study of the Sr2IrO4 under high magentic field, high presure and temperature. The magnetic field study showed disticntively two different regimes as a function of applied in-plane external field. For moderately high magnetic fiels, H>1.5 T, Sr2IrO4 magnetic mode shows behavior consistent with S=1/2 2D Heisenberg model. However, for H<1.5 T, it shows anisotropic behavior as a function of external field due to interlayer couling. Ths study showed that while for even for moderate field, the magentic behavior is consistent with suggested two-dimensional effective S=1/2 Hamiltonian, for in low fields it showed anisotropic behavior. For future studies, the important role of the interlayer coupling should be considered.
Graduation Semester
2018-08
Type of Resource
text
Permalink
http://hdl.handle.net/2142/101467
Copyright and License Information
Copyright 2018 Yewon Gim

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