Tuesday, July 16, 2013

1307.3742 (Eui-Sup Lee et al.)

Evaluating the Seebeck effect at the atomic scale    [PDF]

Eui-Sup Lee, Sanghee Cho, Ho-Ki Lyeo, Yong-Hyun Kim
The atomic variations of electronic wavefunctions at surface and electron scattering near a defect can be detected by measuring electron tunnelling currents across a vacuum gap and alternatively by tracing thermoelectric voltages over a temperature bias. Because the Seebeck effect is associated with electron diffusion, it is very unclear how the thermoelectric signal is related to the atomic-scale wavefunctions and what the role of temperature is at such a length scale. Here we show that coherent electron and heat transport through a point-like contact produces an atomic Seebeck effect. The interplay between the mesoscopic Seebeck coefficient and interfacial thermal conductance at the contact can lead to the differential imaging of the local density of states at the Fermi energy with the atomic resolution. We also discovered that the Seebeck coefficient is conceptually connected to the electronic heat capacity and quantum of thermal conductance in a material by introducing the statistically defined Fermi temperature.
View original: http://arxiv.org/abs/1307.3742

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