Phys.org  May 10, 2023 Topological semimetals have advantages in achieving highly sensitive, low energy photodetection with ultrafast operation. Although various semimetals have been explored recently, new semimetals are still being pursued for high-responsivity photodetectors with broadband response. Researchers in China reported a pressure-induced semiconductor–semimetal transition in two-dimensional wide-band semiconducting lead iodide (PbI2). The photocurrent under visible light showed abrupt increases by two orders of magnitude at ≈25 GPa, where the crystalline structure transforms from the Pnma to I4/MMM phase. The responding band expanded from visible light to at least the telecom wavelength 1550 nm. The spectra of PbI2 suggested that […]