Regensburg 2022 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.31: Poster

Wednesday, September 7, 2022, 18:00–20:00, P2

Tunable 2D phononic crystals — •Yuefeng Yu, Jan Kirchhof, Bianca Hofer, Oguzhan Yucel, and Kirill Bolotin — Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany

In the field of phononics, periodic patterning controls vibration and thereby flow of heat and sounds based on its phononic band structure. This kind of structures name as phononic crystals (PnCs). Bandgaps of PnCs arise their potentials in low-dissipation mechanical states towards efficient waveguide and stable mechanical qubit. By combining highly flexible suspended two-dimension (2D) materials and PnCs into 2D-capacitor framework, applying pressure through voltage and thereby changing the unit size of periodic pattern to tune the phononic bandgap is accomplishable. For now, we are playing the PnCs in graphene and 2D MoS2 with hexagonal lattice and microscale cavity. From cavity interferometric measurement, the periodic pattern can effectively block a frequency-range of vibration modes and establish the 1.5MHz-wide phononic bandgap of 2D-MoS2 PnCs. By varying the incident-laser power and gating voltage, position of bandgap moves in MHz-frequency-range. With the supporting of simulation, graphene shows a much higher tunability of the width and position in frequency of phononic bandgap than MoS2. All of these suggests a potential playground for quantum information and phase transition in mechanical.