Pressure-induced electronic transition in vacancy-ordered halide double perovskite Cs2TeBr6
Abstract
We report high-pressure x-ray diffraction, Raman scattering, photoluminescence, and absorption measurements on vacancy-ordered halide double perovskite Cs2TeBr6. An electronic transition becomes apparent at around 2.3 GPa, characterized by anomalous behavior in the normalized pressure as a function of the Eulerian strain, a broad minimum in Raman linewidth, and a slope change in the linear pressure variation of a Raman mode frequency. The large compressibility and the observed anomalies in Raman scattering suggest that the material is soft and exhibits a strong electron–phonon coupling. The broad emission below the bandgap is attributed to the recombination of self-trapped excitons. The Cs2TeBr6 crystal, consisting of undistorted octahedra, exhibits substantial emission enhancement and bandgap narrowing under pressure. The electronic transition is further supported by the observed emission maximum and a small kink in the pressure variation of the bandgap at around 2.3 GPa.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (8)
Debabrata Samanta
Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata 1 , Mohanpur Campus, Mohanpur, Nadia 741246, West Bengal,
Suvashree Mukherjee
Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata 1 , Mohanpur Campus, Mohanpur, Nadia 741246, West Bengal,
Asish Kumar Mishra
National Centre for High Pressure Studies, Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata 1 , Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal,
Bhagyashri Giri
National Centre for High Pressure Studies, Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata 1 , Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal,
Sonu Pratap Chaudhary
Department of Chemical Sciences, and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata 2 , Mohanpur 741246,
Konstantin Glazyrin
Sayan Bhattacharyya
Department of Chemical Sciences, and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata 2 , Mohanpur 741246,
Goutam Dev Mukherjee
Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata 1 , Mohanpur Campus, Mohanpur, Nadia 741246, West Bengal,