Linear and Circularly Polarized Raman and Photoluminescence of a Chiral 2D Hybrid Lead-Halide Perovskite

Two-dimensional (2D) hybrid organic−inorganic lead halide perovskites are an exciting class of semiconducting materials for both fundamental study and applications in spin-based electronic devices. Single crystals of needle shaped, enantiomerically-pure methylbenzylammonium lead iodide (R-MBA)₂PbI₄ [R = right handed; MBA = C₆H₅C₂H₄NH₃] perovskites were probed optically using CW, visible lasers. Raman and photoluminescence spectra were collected as a function of both linear and circular polarized beams, permitting assignment of the phonons and excitons based on symmetry. Low frequency Raman modes (<20 cm^-1) are particularly sensitive to the differences in rotation of the circular polarization. The temperature dependence [down to 1.6 K] of both sets of the optical spectra were also analyzed. Present measurements include magneto-Raman and magneto-PL via unique instrumentation at NIST at fields up to 9 Tesla.