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11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Spin-dependent thermoelectric effects in graphene-based spin valves.
Minggang Zeng1, Wen Huang, Gengchiau Liang
1Department of Electrical and Computer Engineering, 4 Engineering Drive 3, National University of Singapore, Singapore 117576, Republic of Singapore. phyzengm@nus.edu.sg
Nanoscale
|November 16, 2012
Summary
Spin valves using zigzag graphene nanoribbons exhibit controllable thermal magnetoresistance and Seebeck effects. These findings highlight potential for low-power spin caloritronics and information storage applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spintronics
Background:
- Spin valves are crucial for spintronics, but understanding their thermoelectric properties under varying magnetic configurations is essential.
- Graphene nanoribbons offer unique electronic properties for advanced device applications.
Purpose of the Study:
- Investigate spin-dependent thermoelectric effects in zigzag graphene nanoribbon (ZGNR) based spin valves.
- Explore the influence of magnetic configurations on thermal transport and magnetic properties.
- Assess the potential for low-power spin caloritronics and data storage.
Main Methods:
- First-principles calculations.
- Non-equilibrium Green's function (NEGF) formalism.
- Analysis of electron transport, Seebeck coefficients, power factor, thermal conductance, and figure of merit (ZT).
Main Results:
- Electron transport and thermoelectric properties are highly dependent on magnetic configurations.
- A significant thermal magnetoresistance (MR) effect was observed, controllable via magnetic switching.
- A large and controllable magneto Seebeck ratio was achieved due to differing Seebeck coefficients.
- The figure of merit (ZT) reached 0.15 at room temperature (excluding phonon scattering).
- Thermally-controlled magnetic distributions, including local magnetic moments, were identified.
Conclusions:
- ZGNR-based spin valves demonstrate significant potential for low-power spin caloritronics due to controllable thermal MR and Seebeck effects.
- The thermally-controlled magnetic moment suggests possible applications in information storage devices.
- Further research, including phonon scattering, is warranted to optimize ZT values.
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