Exciton-induced Charge Fluctuations in One-dimensional Quasi-periodic “Metallic” Chains: A Possible Embodiment of Room Temperature Superconductivity

It is well known that a purely periodic chain of odd-electron atoms, nominally expected to exhibit metallic behavior, is unstable to charge/spin spatial displacement which lowers its ground state energy by gapping its multi-degenerate Fermi surface, in this case consisting of nesting parallel sheets. It is largely for these reasons that superconductivity is not observed in highly one-dimensional metals -- it is simply energetically more favorable for CDW/SDW gaps to form, rather than a BCS state, at least one mediated by electron-phonon coupling. In this talk, we explore the hypothetical electronic properties of a nominally ``metallic'' quasi-periodic chain using both an analytical approach and computationally with density functional theory, searching for configurations which yield ``gap-lets'' sufficiently small to permit the formation of BCS pairs as the new energetically favored ground state. The particular embodiment we examine is a string of aluminum atoms with interatomic spacing determined by a Fibonacci sequence. We propose a path to attempt synthesis of such a structure for experimental examination, and perhaps leading to an entirely new class of higher temperature superconductors¹.
¹ Grant, P.M., Quantum Stud: Math. Found. (2018) 5:83-88 DOI 10.1007/s405409-017-0129-7