Vacuum Ultraviolet Reflection Spectra of Ethyl-Ammonium Halides and Ethyl-Ammonium Cadmium Halides

摘要

Layered perovskite-type materials of alkylammonium metal halides, (C_nH_(2n+1)NH_3)_2MX_4 (n = 1, 2, …, M = Cd, Mn, Cu, …, X = Cl, Br, I, cause the sequential structural phase transitions,owing to the rearrangements of the alkylammonium chains. Many studies have been made on the transitions. ~(1-5) On the other hand, the optical properties in the visible and ultraviolet regions have been also well studied, and the studies have clarified interesting physical properties, such as the exciton self-trapping, ~(6)) the anti-ferromagnetism and the magnon-associated excitonic transitions.~(7-9)) However, in the materials, the optical properties in the vacuum ultraviolet (VUV) region have not yet been studied enough.