Table 2.

Properties of time-reversal-symmetric constant pairing functions in a 2D model of FeSe at Γ.

Δ	Matrix	mx	my	mz	c4z	Node	Lowest excitation
${\tilde{\mathrm{\Delta }}}_1$	iσy	+	+	+	+	Gapped	No
${\tilde{\mathrm{\Delta }}}_2$	ρziσy	+	+	+	−	Gapped	Yes
${\tilde{\mathrm{\Delta }}}_3$	ρyσziσy	+	+	+	+	Gapped	Yes
${\tilde{\mathrm{\Delta }}}_{4a}$	ρyσxiσy	−	+	−	${\tilde{\mathrm{\Delta }}}_{4b}$	Line	Yes
${\tilde{\mathrm{\Delta }}}_{4b}$	ρyσyiσy	+	−	−	$-{\tilde{\mathrm{\Delta }}}_{4a}$	Line	Yes
${\tilde{\mathrm{\Delta }}}_5$	ρxiσy	−	−	+	−	Point	Yes

Here, ${\tilde{\mathrm{\Delta }}}_1={\mathrm{\Delta }}_{1}i{\sigma }_y$, ${\tilde{\mathrm{\Delta }}}_2={\mathrm{\Delta }}_2{\rho }_{z}i{\sigma }_y$, ${\tilde{\mathrm{\Delta }}}_3={\mathrm{\Delta }}_3{\rho }_y{\sigma }_{z}i{\sigma }_y$, ${\tilde{\mathrm{\Delta }}}_{4}a={\mathrm{\Delta }}_{4a}{\rho }_y{\sigma }_{x}i{\sigma }_y$, ${\tilde{\mathrm{\Delta }}}_{4}b={\mathrm{\Delta }}_{4b}{\rho }_y{\sigma }_{y}i{\sigma }_y$, and ${\tilde{\mathrm{\Delta }}}_5={\mathrm{\Delta }}_5{\rho }_{x}i{\sigma }_y$. The second column shows the result of transformation $u_g\mathrm{\Delta }{u}_g^T$ by g = m_x, m_y, m_z or c_4z. The signs + and − mean +Δ and −Δ, respectively.