1. Quantum-Well Bound States in Graphene Heterostructure Interfaces
- Author
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Zhongwei Dai, Zhaoli Gao, Chang-Yong Nam, Jiadong Zang, A. T. Charlie Johnson, Nikhil Tiwale, Qicheng Zhang, Samuel A. Tenney, Richard M. Osgood, Calley N. Eads, Jerzy T. Sadowski, Sergey S. Pershoguba, and Ashwanth Subramanian
- Subjects
Physics ,Condensed matter physics ,Graphene ,Phonon ,General Physics and Astronomy ,Fano resonance ,02 engineering and technology ,Type (model theory) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,law.invention ,law ,Quantum dot ,0103 physical sciences ,Continuum (set theory) ,010306 general physics ,0210 nano-technology ,Bilayer graphene ,Quantum well - Abstract
We present experimental evidence of electronic and optical interlayer resonances in graphene van der Waals heterostructure interfaces. Using the spectroscopic mode of a low-energy electron microscope (LEEM), we characterized these interlayer resonant states up to 10 eV above the vacuum level. Compared with nontwisted, AB-stacked bilayer graphene (AB BLG), an $\ensuremath{\approx}0.2\text{ }\text{ }\AA{}$ increase was found in the interlayer spacing of 30\ifmmode^\circ\else\textdegree\fi{} twisted bilayer graphene (30\ifmmode^\circ\else\textdegree\fi{}-tBLG). In addition, we used Raman spectroscopy to probe the inelastic light-matter interactions. A unique type of Fano resonance was found around the D and G modes of the graphene lattice vibrations. This anomalous, robust Fano resonance is a direct result of quantum confinement and the interplay between discrete phonon states and the excitonic continuum.
- Published
- 2021
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