Thermoelectric transport properties in atomic scale conductors

Area of Science:

• • Condensed matter physics
• • Nanoscale science
• • Materials science

Background:

• • Thermoelectric materials convert heat energy into electrical energy and vice versa.
• • Understanding thermoelectric transport at the atomic scale is crucial for developing efficient nanoscale devices.
• • Atomic junctions present unique quantum phenomena affecting transport properties.

Purpose of the Study:

• • To investigate the thermoelectric transport properties of a single silicon atom junction.
• • To quantitatively study the Seebeck thermopower and thermal conductance.
• • To analyze the contributions of voltage and temperature gradients to electrical and heat currents.

Main Methods:

• • First-principles calculations based on the Landauer-Buttiker formalism.
• • Investigation within the linear response regime.
• • Analysis of the transmission function's energy derivative.

Main Results:

• • Both electrical and heat currents exhibit contributions from voltage and temperature gradients.
• • A finite thermopower is observed only when the energy derivative of the transmission function is non-zero.
• • An anomaly in thermopower was detected in the tunneling regime, consistent with thermodynamic laws.

Conclusions:

• • The study provides quantitative insights into thermoelectric transport in atomic scale silicon conductors.
• • The observed thermopower anomaly does not violate thermodynamic principles.
• • Findings contribute to the understanding of quantum effects in nanoscale thermoelectric devices.