Temperature dependent angle-resolved photoemission and x-ray diffraction of CsPbBr3

CsPbBr3 shares the high efficiency in light harvesting with hybrid organic-inorganic lead halide perovskites. Angle-resolved photoemission of the valence band has so far only shown bands of the cubic structure at room temperature although the system is orthorhombic below about 360 K. We demonstrate weak orthorhombic features in the band structure at 300 K which become very pronounced at low temperature, including an extra valence band maximum at Γ. We perform temperature depedent x-ray diffraction and compare the angle-resolved photoemission data to density functional theory calculations based on the x-ray diffraction. After having recently clarified the absence of a Rashba splitting and large polarons in angle resolved photoemission data [1,2], we will attempt to draw conclusions from angle resolved photoemission concerning aspects relevant for the high efficiency of lead halide perovskites.

[1] M. Sajedi et al., Phys. Rev. B 102, 081116(R) (2020)

[2] M. Sajedi et al., Phys. Rev. Lett. 128, 176405 (2022)