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Fabricating van der Waals Heterostructures with Precise Rotational Alignment
Published on: July 5, 2019
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Electrically tunable giant Nernst effect in two-dimensional van der Waals heterostructures
Gabriele Pasquale1,2, Zhe Sun1,2, Guilherme Migliato Marega1,2
1Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Nature Nanotechnology
|July 2, 2024
Summary
Researchers developed a new graphene/indium selenide heterostructure for a tunable Nernst effect. This platform shows potential for advanced energy conversion and spintronics at low temperatures.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Thermoelectrics
Background:
- The Nernst effect is a key transverse thermoelectric phenomenon with applications in energy conversion, thermoelectrics, and spintronics.
- High performance and electrical tunability of the Nernst effect at low temperatures remain challenging.
Purpose of the Study:
- To demonstrate a large and electrically tunable Nernst effect using a novel material platform.
- To explore the potential of graphene/indium selenide heterostructures for thermoelectric applications.
Main Methods:
- Fabrication of a graphene/indium selenide heterostructure in a field-effect geometry.
- Electrical characterization of the Nernst effect and photovoltage measurements.
- Investigation of the Nernst coefficient at ultralow temperatures and low magnetic fields.
Main Results:
- Achieved a large and electrically tunable Nernst effect with an on/off ratio of 10^3.
- Observed a significantly enhanced photo-Nernst signal in the heterostructure compared to individual components.
- Recorded a record-high Nernst coefficient of 66.4 μV K⁻¹ T⁻¹ at ultralow temperatures and low magnetic fields.
Conclusions:
- The graphene/indium selenide heterostructure provides a new platform for exploring and manipulating the Nernst effect.
- Demonstrated the first electrical tunability of the Nernst effect, paving the way for novel device applications.
- The observed high Nernst coefficient is crucial for advancements in quantum information and low-temperature physics.
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