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Fabricating van der Waals Heterostructures with Precise Rotational Alignment
Published on: July 5, 2019
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Terahertz phonon engineering with van der Waals heterostructures
Yoseob Yoon1,2,3, Zheyu Lu4,5, Can Uzundal4,6
1Department of Physics, University of California, Berkeley, CA, USA. y.yoon@northeastern.edu.
Nature
|June 26, 2024
Summary
Researchers engineered terahertz phonons using van der Waals heterostructures. This breakthrough enables ultrabroadband acoustic devices and advanced quantum circuits by precisely controlling terahertz acoustic waves.
Area of Science:
- Solid State Physics
- Materials Science
- Nanotechnology
Background:
- Phonon engineering at gigahertz frequencies is crucial for current technologies like acoustic filters and quantum transducers.
- Terahertz (THz) phonon engineering promises higher bandwidth, faster speeds, and higher-temperature quantum circuits.
- Existing methods for THz phonon engineering face challenges in subnanometer material control and efficient THz phonon coupling.
Purpose of the Study:
- To demonstrate efficient generation, detection, and manipulation of terahertz phonons.
- To overcome limitations in current THz phonon engineering techniques.
- To enable new applications in THz phononic devices and quantum circuits.
Main Methods:
- Utilized van der Waals heterostructures with atomically thin layers for precise material integration.
- Employed few-layer graphene as an ultrabroadband transducer for converting near-infrared pulses to THz acoustic-phonon pulses (up to 3 THz).
- Used a monolayer tungsten diselenide (WSe2) as a sensor, leveraging exciton-phonon coupling for high-fidelity readout.
Main Results:
- Successfully generated, detected, and manipulated THz phonons using the designed heterostructure.
- Demonstrated high-Q terahertz phononic cavities.
- Showcased efficient blocking of THz phonon transmission using a WSe2 monolayer in hexagonal boron nitride.
- Obtained heterointerface force constants by comparing measurements to a nanomechanical model.
Conclusions:
- The developed platform enables terahertz phononic spectroscopy.
- This work paves the way for THz phononic metamaterials for ultrabroadband acoustic filters and modulators.
- The findings open new avenues for thermal engineering and advanced quantum technologies.
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