Spin-split bands cause the indirect band gap of (CH${}_3$NH${}_3$)PbI${}_3$: Experimental evidence from circular photogalvanic effect

Abstract

Long carrier lifetimes and diffusion lengths form the basis for the successful application of the organic-inorganic perovskite (CH${}_3$NH${}_3$)PbI${}_3$ in solar cells and lasers. The mechanism behind the long carrier lifetimes is still not completely understood. Spin-split bands and a resulting indirect band gap have been proposed by theory. Using near band-gap left-handed and right-handed circularly polarized light we induce photocurrents of opposite directions in a single-crystal (CH${}_3$NH${}_3$)PbI${}_3$ device at low temperature ($4\mathrm{K}$). The phenomenom is known as the circular photogalvanic effect and gives direct evidence for phototransport in spin-split bands. Simultaneous photoluminecence measurements show that the onset of the photocurrent is below the optical band gap. The results prove that an indirect band gap exists in (CH${}_3$NH${}_3$)PbI${}_3$ with broken inversion symmetry as a result of spin-splittings in the band structure. This information is essential for understanding the photophysical properties of organic-inorganic perovskites and finding lead-free alternatives. Furthermore, the optically driven spin currents in (CH${}_3$NH${}_3$)PbI${}_3$ make it a candidate material for spintronics applications.

References in corpus (28)

• Direct Measurement of the Exciton Binding Energy and Effective Masses for Charge carriers in an Organic-Inorganic Tri-halide Perovskite
• Relativistic Solar Cells
• Determination of the exciton binding energy and effective masses for the methylammonium and formamidinium lead tri-halide perovskite family
• Relativistic quasiparticle self-consistent electronic structure of hybrid halide perovskite photovoltaic absorbers
• Local polar fluctuations in lead halide perovskite crystals
• Control over topological insulator photocurrents with light polarization
• Hidden spin polarization in inversion-symmetric bulk crystals
• Indirect to direct bandgap transition in methylammonium lead halide perovskite
• Generation and Electric Control of Spin-Coupled Valley Current in WSe2
• Giant Rashba Splitting in CH3NH3PbBr3 Organic-Inorganic Perovskite
• Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite
• Rotational Dynamics of Organic Cations in CH3NH3PbI3 Perovskite
• Ferroelectricity and Rashba effect in GeTe
• Relativistic origin of slow electron-hole recombination in hybrid halide perovskite solar cells
• Unraveling the exciton binding energy and the dielectric constant in single crystal methylammonium lead tri-iodide perovskite
• From soft harmonic phonons to fast relaxational dynamics in CH${}_3$NH${}_3$PbBr${}_3$
• Interplay between organic cations and inorganic framework and incommensurability in hybrid lead-halide perovskite CH3NH3PbBr3
• Impact of Small Phonon Energies on the Charge-Carrier Lifetimes in Metal-Halide Perovskites
• Photon Drag Effect in (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ Three Dimensional Topological Insulators
• Demonstration of Rashba spin splitting in GaN-based heterostructures
• Temperature-dependent optical spectra of single-crystal (CH${}_3$NH${}_3$)PbBr${}_3$ cleaved in ultrahigh vacuum
• Spatially resolved studies of the phases and morphology of methylammonium and formamidinium lead tri-halide perovskites
• Ultrafast polarization control of zero-bias photocurrent and terahertz emission in hybrid organic perovskites
• Optical Spintronics in Organic-Inorganic Perovskite Photovoltaics
• Circular Photogalvanic Effect in Organometal Halide Perovskite CH${}_3$NH${}_3$PbI${}_3$
• Spin and orbital mechanisms of the magneto-gyrotropic photogalvanic effects in GaAs/AlGaAs quantum well structures
• Phonon-assisted spin splitting in centrosymmetric crystals
• Robust Bloch character at the band edges of hybrid halide perovskites

Cited by in corpus (15)

• Giant Fine Structure Splitting of the Bright Exciton in a Bulk MAPbBr${}_3$ Single Crystal
• Static Rashba Effect by Surface Reconstruction and Photon Recycling in the Dynamic Indirect Gap of APbBr3 (A = Cs, CH3NH3) Single Crystals
• Dynamic Rashba-Dresselhaus Effect
• Influence of Disorder and Anharmonic Fluctuations on the Dynamical Rashba Effect in Purely Inorganic Lead-Halide Perovskites
• Tunable spin textures in polar antiferromagnetic hybrid organic inorganic perovskites by electric and magnetic fields
• Polar or nonpolar? That is not the question for perovskite solar cells
• Structural dynamics in hybrid halide perovskites: Bulk Rashba splitting, spin texture, and carrier localization
• Photoinduced Rashba spin to charge conversion via interfacial unoccupied state
• Topological polarons in halide perovskites
• Pressure and Inversion Symmetry Breaking Field Driven First Order Phase Transition and Formation of Dirac Circle in Perovskites
• Lead-free Hybrid Perovskite: An Efficient Room Temperature Spin Generator via Large Interfacial Rashba effect
• Ultrafast acoustic phonon scattering in CH${}_3$NH${}_3$PbI${}_3$ revealed by femtosecond four-wave mixing
• Detection of quantum geometric tensor by nonlinear optical response
• Rashba Effect and Raman Spectra of Tl${}_2$O/PtS${}_2$ Heterostructure
• Distinguishing between dynamical and static Rashba effects in hybrid perovskite nanocrystals using transient absorption spectroscopy