Aharonov-Bohm Effect at liquid-nitrogen temperature: Frohlich superconducting quantum device

The Aharonov-Bohm (AB) effect has been accepted and has promoted interdisciplinary scientific activities in modern physics. To observe the AB effect in condensed matter physics, the whole system needs to maintain phase coherence, in a tiny ring of the diameter 1 micrometer and at low temperatures below 1 K. We report that AB oscillations have been measured at high temperature 79 K by use of charge-density wave (CDW) loops in TaS3 ring crystals. CDW condensate maintained macroscopic quantum coherence, which extended over the ring circumference 85 micrometer. The periodicity of the oscillations is h/2e in accuracy within a 10 percent range. The observation of the CDW AB effect implies Frohlich superconductivity in terms of macroscopic coherence and will provide a novel quantum interference device running at room temperature.