Toward a room temperature Schafroth superconductor based on charged excitonic complexes
In 1954, Schafroth proposed a mechanism for superconductivity that is physically possible, but ended up not being the explanation of the well known BCS superconductors. The proposal argued correctly that a Bose condensate of charged bosons should also be a superconductor. In 1996, V.I. Yudson proposed a way to produce a charged boson by attaching two free charges to an exciton in a semiconductor, to make a "quaternion". While that state was never seen in III-V semiconductors, our calculations show that it is predicted to be stable in structures made with monolayers of transition metal dichalcogenide (TMD) materials. We present experimental spectroscopic measurements that agree with this theory, which indicate that we have observed this charged-boson state in this type of structure. This opens up a new path for pursuing room temperature superconductivity.