U51.00006. THz spectroscopy of graphene and graphene nanoribbons using LaAlO3/SrTiO3 nanoscale junctions

Presented by: Erin Sheridan


Abstract

Abstract: We investigate the optical response of graphene and graphene nanoribbons using the broadband nonlinear generation and detection capabilities of nanoscale junctions created at the LaAlO3/SrTiO3 interface [1]. Using the large non-resonant third-order nonlinear susceptibility in SrTiO3, strong difference frequency mixing occurs when the junction is biased, leading to induced polarization that can also be detected at the junction [2,3]. Here we discuss the results of experiments which interrogate the relationship between the THz signal and the gate location with respect to the Dirac point in devices where graphene is coupled to the LaAlO3/SrTiO3 interface. Results show nearly 100% extinction of VIS-NIR light in the graphene, and suggest we may be detecting a surface plasmon resonance. Additional results on individual graphene nanoribbons reinforce this interpretation. [1] C. Cen, et al., Nature Materials 7, 298 (2008). [2] Y. Ma, et al., Nano Lett 13, 2884 (2013). [3] L. Chen, et al., Light: Science & Appl. 8, 24 (2019).

Authors

  • Erin Sheridan
  • Lu Chen
  • Qing Guo
  • Jianan Li
  • Hyungwoo Lee
  • Jung-Woo Lee
  • Chang-Beom Eom
  • Patrick Irvin
  • Jeremy Levy


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