Room-temperature quantum interference in single perovskite quantum dot junctions.

Zheng, Haining; Hou, Songjun; Xin, Chenguang; Wu, Qingqing; Jiang, Feng; Tan, Zhibing; Zhou, Xin; Lin, Luchun et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

The studies of quantum interference effects through bulk perovskite materials at the Ångstrom scale still remain as a major challenge. Herein, we provide the observation of room-temperature quantum interference effects in metal halide perovskite quantum dots (QDs) using the mechanically controllable break junction technique. Single-QD conductance measurements reveal that there are multiple conductance peaks for the CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> and CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>2.15</sub>Cl<sub>0.85</sub> QDs, whose displacement distributions match the lattice constant of QDs, suggesting that the gold electrodes slide through different lattice sites of the QD via Au-halogen coupling. We also observe a distinct conductance 'jump' at the end of the sliding process, which is further evidence that quantum interference effects dominate charge transport in these single-QD junctions. This conductance 'jump' is also confirmed by our theoretical calculations utilizing density functional theory combined with quantum transport theory. Our measurements and theory create a pathway to exploit quantum interference effects in quantum-controlled perovskite materials.