The valley Nernst effect in WSe₂.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• The Nernst effect, a thermal analogue of the Hall effect, involves temperature gradients.
• The spin Nernst effect and valley Hall effect are related phenomena involving spin and valley degrees of freedom.
• The valley Nernst effect, a counterpart to the valley Hall effect, was previously unobserved.

Purpose of the Study:

• To experimentally demonstrate the existence of the valley Nernst effect.
• To investigate valleytronics phenomena using thermal gradients.
• To explore spin-valley coupling in WSe2.

Main Methods:

• Utilized millimeter-sized WSe2 mono-multi-layers.
• Employed the ferromagnetic resonance-spin pumping technique.
• Applied a temperature gradient by off-centering the sample in a radio frequency cavity.
• Addressed a single valley through spin-valley coupling.

Main Results:

• Provided experimental evidence for the valley Nernst effect.
• Detected the valley Nernst effect electrically at room temperature.
• Observed good agreement between the measured valley Nernst coefficient and theoretical predictions.

Conclusions:

• The valley Nernst effect has been experimentally confirmed in WSe2.
• This finding enriches the understanding of Nernst effect-related phenomena and valleytronics.
• The study demonstrates the potential of WSe2 for room-temperature valleytronics applications.