Pressure-induced superconductivity in the photoelectric semiconductor BiSeI

AV BVI CVII (A = Bi, Sb; B = S, Se; C = I, Br) semiconductors are promising materials in photoelectric applications and exhibit high tunability of electronic properties. Here, we systematically study the electrical transport, structural, and vibrational properties of photoelectric semiconductor BiSeI at high pressure. With increasing pressure, a small drop in the resistance curve starts to appear at PC - 27.4 GPa and zero resistance conductivity is eventually achieved at 40.4 GPa, indicating the occurrence of a superconducting transition. Combined with high-pressure Raman scattering, synchrotron XRD measurements, and theoretical calculations, we demonstrate that this superconductivity originates from a high-pressure phase with space group P4/nmm. Upon further compression, TC initially increases and then changes marginally with a nearly constant 5.6 K above 40.0 GPa, suggesting the robustness of this superconductivity. Our findings will shed light on exploring exotic properties in low-dimensional systems via pressure treatment.