Physics

Mechanically-tunable bandgap closing in 2D graphene phononic crystals

J. N. Kirchhof and K. I. Bolotin

Discover a groundbreaking tunable phononic crystal that transitions between mechanical insulation and conductivity, developed by Jan N. Kirchhof and Kirill I. Bolotin. This research unveils how tuning the device with gate voltage can manipulate a crucial bandgap, paving the way for phonon logic and advanced mechanical coupling applications.

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Abstract

This paper presents a tunable phononic crystal that can switch between mechanically insulating and conductive states. Simulations show a bandgap for out-of-plane phonons (48.8–56.4 MHz) under biaxial tension, closable by increasing uniaxial tension. A realistic device design using suspended graphene allows tuning via gate voltage. The bandgap closing is probed via acoustic transmission measurements, persisting even with surface contaminants and tension variations. The system acts as a MHz-phonon transistor with a 10⁵ on/off ratio, suitable for phonon logic and tunable coupling between mechanical entities.

Publisher

npj 2D Materials and Applications

Published On

Feb 23, 2023

Authors

Jan N. Kirchhof, Kirill I. Bolotin