Spin-orbit coupling in transition metal dichalcogenides (TMDCs) causes spin-valley locking, giving rise to unconventional optical, transport, and superconducting properties. In this paper, we propose exotic superconductivity in bilayer group-IV TMDCs by symmetry control. The sublattice-dependent “hidden” spin-orbit coupling arising from local inversion symmetry breaking in the crystal structure may stabilize the odd-parity superconductivity by purely $s$-wave local pairing interaction. The stability of the odd-parity superconducting state depends on the bilayer stacking. The $2{\mathrm{H}}_b$ stacking in $\text{Mo}{X}_2$ and $\text{W}{X}_2$ ($X=\mathrm{S}$,Se) favors the odd-parity superconductivity due to interlayer quantum interference. On the other hand, the odd-parity superconductivity is suppressed by the $2{\mathrm{H}}_a$ stacking of ${\mathrm{NbSe}}_2$. Calculating the phase diagram of the tight-binding model derived from first-principles band calculations, we conclude that the intercalated bilayer ${\mathrm{MoS}}_2$ and ${\mathrm{WS}}_2$ are candidates for a new class of odd-parity superconductors by spin-orbit coupling.

• Received 23 March 2017
• Revised 29 June 2017

DOI:https://doi.org/10.1103/PhysRevB.96.054501