Surface-state enhancement of tunneling thermopower on the Ag(111) surface
| Autor: | Simon J. Kelly, Jorge Cerdá, Petro Maksymovych |
|---|---|
| Přispěvatelé: | Oak Ridge National Laboratory (US), Department of Energy (US), Ministerio de Ciencia e Innovación (España), Ministerio de Economía y Competitividad (España) |
| Rok vydání: | 2014 |
| Předmět: |
Silver
Condensed matter physics Tunneling Chemistry General Engineering General Physics and Astronomy Nanoparticle engineering.material Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Resonance Electron transport chain Resonance (particle physics) Transmission (telecommunications) Thermopower Condensed Matter::Superconductivity Seebeck coefficient Thermoelectric effect engineering General Materials Science Noble metal Landauer Quantum tunnelling Thermovoltage |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1936-086X |
| Popis: | Thermoelectric effects in tunnel junctions are currently being revisited for their prospects in cooling and energy harvesting applications, and as sensitive probes of electron transport. Quantitative interpretation of these effects calls for advances in both theory and experiment, particularly with respect to the electron transmission probability across a tunnel barrier which encodes the energy dependence and the magnitude of tunneling thermopower. Using noble metal surfaces as clean model systems, we demonstrate a comparatively simple and quantitative approach where the transmission probability is directly measured experimentally. Importantly, we estimate not only thermovoltage, but also its energy and temperature dependencies. We have thus resolved surface-state enhancement of thermovoltage, which manifests as 10-fold enhancement of thermopower on terraces of the Ag(111) surface compared to single-Atom step sites and surface-supported nanoparticles. To corroborate experimental analysis, the methodology was applied to the transmission probability obtained from first-principles calculations for the (111) surfaces of the three noble metals, finding good agreement between overall trends. Surface-state effects themselves point to a possibility of achieving competitive performance of all-metal tunnel junctions when compared to molecular junctions. At the same time, the approach presented here opens up possibilities to investigate the properties of nominally doped or gated thermoelectric tunnel junctions as well as temperature gradient in nanometer gaps. A portion of this research (S.K.) was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. A portion of this research (P.M.) was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, U.S. Department of Energy. J.I.C. acknowledges financial support from the Spanish Ministerio de Economía y Competitividad (Grant Nos. MAT2010-18432 and MAT2013-47878-C2-R). |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|