Tunable room-temperature spin-selective optical Stark effect in solution-processed layered halide perovskites
Giovanni, D., W.K. Chong, H.A. Dewi, K. Thirumal, I. Neogi, Ramamoorthy Ramesh, S. Mhaisalkar, N. Mathews, T.C. Sum
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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