Giant Nernst effect and lock-in currents at magic angles in (TMTSF)2PF6

Area of Science:

• Condensed matter physics
• Materials science
• Low-temperature physics

Background:

• The organic conductor (TMTSF)2PF6 exhibits complex electronic properties under pressure.
• Understanding charge transport in low-dimensional organic materials is crucial for developing new electronic devices.

Purpose of the Study:

• To investigate the thermoelectric response of (TMTSF)2PF6 under hydrostatic pressure.
• To explore the influence of magnetic field orientation on charge transport phenomena.

Main Methods:

• Measurements of the thermoelectric signal along the a-axis of (TMTSF)2PF6.
• Application of 10 kbar hydrostatic pressure.
• Rotation of an applied magnetic field relative to the crystal axes.

Main Results:

• Observed resonant-like Nernst signals with a significant sign change at specific magnetic field orientations ('Lebed magic angles').
• Demonstrated that the electrical current becomes 'locked in' to interchain directions near these magic angles.
• Found signal amplitudes orders of magnitude larger than predicted by conventional Boltzmann transport theory.

Conclusions:

• The findings indicate a breakdown of conventional transport theory in (TMTSF)2PF6 under specific conditions.
• The 'current locking' phenomenon at magic angles suggests novel charge transport mechanisms in this organic conductor.
• This study opens new avenues for exploring exotic electronic states in low-dimensional organic materials.