Die Mischna, ʾAḇôṯ (Väter) : [Seder 4, Nezikin, Traktat 9]

Text, Übers. u. Erklärung nebst e. textkrit. Anhang von Karl Marti u. Georg Beer

I︠U︡zhnoe slavi︠a︡nstvo, Turt︠s︡īi︠a︡ i sopernichestvo evropeĭskikh pravitelśtv na balkanskom poluostrovi︠e︡ : istoriko-politicheskīe ocherki /

Includes bibliographical references.

Exotic Physics in the Negative-U, Extended-Hubbard Model for Barium Bismuthates?

We point out possibilities for exotic physics in barium bismuthates, from a detailed study of the negative-U, extended-Hubbard model proposed for these systems. We emphasize the different consequences of electronic and phononic mechanisms for negative U. We show that, for an electronic mechanism, the semiconducting phases must be unique, with their transport properties dominated by charge ± 2e Cooperon bound states. This can explain the observed difference between the optical and transport gaps. We propose other experimental tests for this novel mechanism of charge transport.