Unidirectional Seebeck detection of the Néel vector in two-dimensional tetragonal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="script">PT</mml:mi></mml:math>-symmetric antiferromagnetic materials

The efficient detection of the reversal (${180}^{\ensuremath{\circ}}$ rotation) of the N\'eel vector is one of the crucial tasks in antiferromagnetic spintronics. Here, we propose a thermal approach to detect the reversal of the N\'eel vector in the tetragonal $\mathcal{PT}$ antiferromagnetic materials through the unidirectional Seebeck effect (USE). Being different from the previous works in which USE stems from the global Rashba spin-orbit coupling (SOC) or asymmetric magnon scattering, we find that the USE originates from the coupling of the hidden Rashba SOC and the N\'eel vector in the tetragonal $\mathcal{PT}$ antiferromagnetic materials in the absence of the global Rashba SOC. Using a generic minimal model, we analyze the behaviors of the USE for the two-dimensional tetragonal lattice $\mathcal{PT}$ antiferromagnet. Importantly, it is found that when the N\'eel vector is reversed, the sign of the USE changes, which can be utilized to detect the reversal of the N\'eel vector.