Structural dynamics in hybrid halide perovskites: Bulk Rashba splitting, spin texture, and carrier localization

Abstract

The extended carrier lifetime in hybrid halide perovskites was attributed to a quasi-indirect band gap that arises due to Rashba splitting in both conduction and valence band edges. In this paper, we present results for an effective relativistic band structure of (CH3NH3)PbI3 with the focus on the dispersion of electronic states near the band edges of (CH3NH3)PbI3 affected by thermal structural fluctuations. We establish a relation between the magnitude of Rashba splitting and a deviation of Pb-atom from its centrosymmetric site position in the PbI6 octahedron. For the splitting energy to reach the thermal energy kT~26 meV (room temperature), the displacement should be of the order 0.3 Ang, which is far above the static displacements of Pb-atoms in the tetragonal phase of (CH3NH3)PbI3. The significant dynamic enhancement of the Rashba splitting observed at earlier simulation times (less than 2 ps) later weakens and becomes less than the thermal energy despite the average displacement of Pb-atoms remaining large (0.37 Ang). It is randomization of Pb-displacement vectors and associated cancelation of the net effective magnetic field acting on electrons at the conduction band edge is responsible for reduction of the Rashba splitting. The lattice dynamics also leads to deterioration of Bloch character for states in the valence band leading to subsequent localization of holes, which affects bipolar mobility of charge carriers in (CH3NH3)PbI3. These results call into question the quasi-indirect band gap as a reason for the long carrier lifetime observed in (CH3NH3)PbI3 at room temperature. An alternative mechanism involves dynamic localization of holes and their reduced overlap with electrons in reciprocal space.

arXiv comment12 pages, 11 figures, 1 table

References in corpus (13)

• Relativistic quasiparticle self-consistent electronic structure of hybrid halide perovskite photovoltaic absorbers
• Indirect to direct bandgap transition in methylammonium lead halide perovskite
• Giant Rashba Splitting in CH3NH3PbBr3 Organic-Inorganic Perovskite
• Relativistic origin of slow electron-hole recombination in hybrid halide perovskite solar cells
• Ferroelectric Rashba Semiconductors as a novel class of multifunctional materials
• Spin-split bands cause the indirect band gap of (CH${}_3$NH${}_3$)PbI${}_3$: Experimental evidence from circular photogalvanic effect
• Temperature Dependence of the Energy Levels of Methylammonium Lead Iodide Perovskite from First Principles
• Generalized Inverse Participation Ratio as a Possible Measure of Localization for Interacting Systems
• Unfolding the band structure of disordered solids: from bound states to high-mobility Kane fermions
• Dynamic Symmetry Breaking and Spin Splitting in Metal Halide Perovskites
• Localization of electronic states in III-V semiconductor alloys: a comparative study
• Temperature dependence of the bulk Rashba splitting in the bismuth tellurohalides
• Phonon-assisted spin splitting in centrosymmetric crystals

Cited by in corpus (7)

• Unraveling the water degradation mechanism of CH${}_3$NH${}_3$PbI${}_3$
• Mixed Formamidinium-Methylammonium Lead Iodide perovskite from first-principles: Hydrogen-bonding impact on the electronic properties
• Exploration of the bright and dark exciton landscape and fine structure of MoS${}_2$ (using G${}_0$W${}_0$-BSE)
• Defect tolerance of lead-halide perovskite (100) surface relative to bulk: band bending, surface states, and characteristics of vacancies
• Electronic properties of Pb-I deficient lead halide perovskites
• Length-gauge optical matrix elements in WIEN2k
• Efficiency of band edge optical transitions of 2D monolayer materials: A high-throughput computational study