Emergence of Superconductivity in Indium Triphosphate via Pressure‐Tuned Interlayer Bond Formation

Tuning interlayer interactions offer an alternative approach to access novel electronic structure and intriguing physical properties in layered materials. Here, the emergence of a new form of superconductivity in two‐dimensional (2D) binary phosphides by strengthening the interlayer coupling with lattice compression is reported. Electrical transport measurements show strong evidence of superconductivity in InP3 with the highest critical temperature (Tc) of 9.5 K at 45.1 GPa. Raman and X‐ray diffraction (XRD) measurements indicate that the interlayer interactions are dramatically modulated under compression, along with the deformation of local In–P bipyramid structure and reduction of the interlayer distances, which eventually results in the formation of In–P bonds between neighboring In–P bipyramids and a Rm to Cmcm structural transition. First‐principles density functional theory (DFT) calculations reveal that pressure enhances the interlayer interactions, which increases the density of states (DOS) near the Fermi surface (N(EF)) and strengthens the electron–phonon coupling. Consequently, this favors the occurrence of superconductivity in compressed InP3. This study not only introduces a new superconductivity phase with enhanced electron–phonon coupling in binary phosphides, but also provides a platform for exploring the pressure effect on interlayer interactions in material systems with corrugated layered structure.