Publication Type:Journal Article
Source:Science Advances, American Association for the Advancement of Science, Volume 2, Number 6 (2016)
Keywords:Calcium compounds, calcium derivative, chemistry, Circularly polarized optical pulse, Dielectric confinement, halogen, Halogens, Inorganic semiconductors, Light-matter coupling, light-matter interactions, oxide, oxides, Perovskite, Perovskite solar cells, Perovskite thin films, quantum theory, semiconductor, semiconductor quantum dots, Semiconductor quantum wells, semiconductors, Solution processability, Stark effect, Straightforward strategy, temperature, thermodynamics, titanium
Ultrafast spin manipulation for opto-spin logic applications requires material systems that have strong spinselective light-matter interaction. Conventional inorganic semiconductor nanostructures [for example, epitaxial II to VI quantum dots and III to V multiple quantum wells (MQWs)] are considered forerunners but encounter challenges such as lattice matching and cryogenic cooling requirements. Two-dimensional halide perovskite semiconductors, combining intrinsic tunable MQW structures and large oscillator strengths with facile solution processability, can offer breakthroughs in this area. We demonstrate novel room-temperature, strong ultrafast spin-selective optical Stark effect in solution-processed (C6H4FC2H4NH3)2PbI4 perovskite thin films. Exciton spin states are selectively tuned by ∼6.3 meV using circularly polarized optical pulses without any external photonic cavity (that is, corresponding to a Rabi energy of ∼55 meV and equivalent to applying a 70 T magnetic field), which is much larger than any conventional system. The facile halide and organic replacement in these perovskites affords control of the dielectric confinement and thus presents a straightforward strategy for tuning light-matter coupling strength. © 2016 The Authors.
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