Institute for Theoretical Physics, University of Regensburg, 93040, Regensburg, Germany.
Institute for Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany.
Nat Commun. 2019 Jan 22;10(1):381. doi: 10.1038/s41467-018-08112-x.
Illumination of atoms by resonant lasers can pump electrons into a coherent superposition of hyperfine levels which can no longer absorb the light. Such superposition is known as a dark state, because fluorescent light emission is then suppressed. Here we report an all-electric analogue of this destructive interference effect in a carbon nanotube quantum dot. The dark states are a coherent superposition of valley (angular momentum) states which are decoupled from either the drain or the source leads. Their emergence is visible in asymmetric current-voltage characteristics, with missing current steps and current suppression which depend on the polarity of the applied source-drain bias. Our results demonstrate coherent-population trapping by all-electric means in an artificial atom.
共振激光对原子的激发可以将电子泵入超精细能级的相干叠加态，从而使原子不再吸收光。这种叠加态被称为暗态，因为荧光发射会被抑制。在这里，我们在一个碳纳米管量子点中报告了这种破坏性干涉效应的全电模拟。暗态是谷（角动量）态的相干叠加，这些态与漏极或源极都解耦。它们的出现可以在不对称的电流-电压特性中看到，其中缺少电流台阶并且电流抑制取决于施加的源-漏偏压的极性。我们的结果表明，通过全电手段在人工原子中实现了相干布居俘获。
