Observation of nuclear-spin Seebeck effect

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Thermoelectric effects, typically electron-based, convert heat to electricity but fail at low temperatures.
• Electronic entropy quenching limits conventional thermoelectric devices at cryogenic conditions.

Purpose of the Study:

• To report the discovery of a novel thermoelectric phenomenon driven by nuclear spins.
• To demonstrate thermoelectric generation at ultralow temperatures using nuclear spins.

Main Methods:

• Utilized a magnetically ordered material, manganese carbonate (MnCO3), with high nuclear spin (55Mn nuclei).
• Incorporated platinum (Pt) contacts to facilitate thermoelectric measurements.
• Observed thermoelectric signals down to 100 mK.

Main Results:

• Demonstrated the nuclear-spin Seebeck effect, a thermoelectric generation mechanism originating from nuclear spins.
• Achieved measurable thermoelectric signals at ultralow temperatures (100 mK).
• Theoretical calculations, including the interfacial Korringa process, accurately reproduced experimental findings.

Conclusions:

• The nuclear-spin Seebeck effect provides a new pathway for thermoelectric energy conversion at ultralow temperatures.
• This discovery expands the scope of thermoelectric science and its technological applications in cryogenic environments.
• Highlights the potential of nuclear spins in novel solid-state phenomena.