Abnormal Seebeck Effect in Vertically Stacked 2D/2D PtSe₂ /PtSe₂ Homostructure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thermoelectric (TE) materials convert heat to electricity.
• Stacked TE materials typically follow a parallel conductor model.
• Vertical stacking can alter transverse Seebeck coefficients.

Purpose of the Study:

• Investigate an abnormal Seebeck effect in stacked 2D PtSe2/PtSe2 homostructures.
• Understand the mechanism behind the interfacial Seebeck effect.
• Explore the relationship between stacking and Seebeck coefficient.

Main Methods:

• Fabrication of stacked PtSe2/PtSe2 homostructures using wet-transfer.
• Application of a transverse temperature gradient.
• Measurement of in-plane Seebeck voltage and coefficient.

Main Results:

• Observed an anomalous in-plane Seebeck voltage at the PtSe2/PtSe2 interface.
• Attributed the effect to carrier-interface interaction, independent of carrier concentration.
• Demonstrated that the in-plane Seebeck coefficient increases with the number of stacked layers.
• Achieved a Seebeck coefficient >188 µV K⁻¹ at 300 K in a four-layer stack.

Conclusions:

• A novel interfacial Seebeck effect exists in stacked PtSe2 homostructures.
• This effect enhances thermoelectric performance beyond conventional models.
• The interfacial Seebeck effect offers new avenues for designing advanced thermoelectric devices.