Graphene/LaAlO₃/SrTiO₃ Heterostructure

Lu Chen

Abstract:

Graphene is a promising tunable plasmonic material in the terahertz regime.  Plasmons can be induced in graphene by femtosecond laser excitation, and their resonance frequency can be gate-tuned over a broad terahertz range¹. Another 2D electron system, the complex-oxide heterostructure LaAlO₃/SrTiO₃, has been shown to exhibit great promise for control and detection of broadband THz emission at extreme nanoscale dimensions². Recently, we have successfully integrated these two platforms: we have created graphene/LaAlO₃/SrTiO₃ structures with high mobility in the graphene channel³ and oxide nanostructures directly underneath the graphene layer⁴.  Now we are working on new experiments that probe graphene plasmonic behavior using this nanoscale THz spectrometer using ultrafast optical techniques. This unprecedented control of THz radiation at 10 nm length scales creates a pathway toward hybrid THz functionality in graphene/LaAlO₃/SrTiO₃ heterostructures.

Acknowledgements:

We gratefully acknowledge financial support from the following agencies and grants: AFOSR FA9550-12-1-0268 (JL, PRI), AFOSR FA9550-12-1-0342 (CBE)), ONR N00014-13-1-0806 (JL, CBE), NSF DMR-1234096 (CBE), and ONR N00014-15-1-2847 (JL) and N00014-16-3152 (JL)

Reference:

1. L. Ju, et al., Nature Nanotech. 6, 630 (2011).
2. Y. Ma, et al., Nano Lett. 13, 2884 (2013).
3. G. Jnawali, et al., arXiv:1602.03128 (2016).

M. Huang, et al., APL Mater. 3, 062502 (2015). 

11/2016