title: Formation of Molecular-Orbital Bands in a Twisted Hubbard Tube: Implications for Unconventional Superconductivity in K_{2}Cr_{3}As_{3}.
abstract: We study a twisted Hubbard tube modeling the [CrAs]_{∞} structure of quasi-one-dimensional superconductors A_{2}Cr_{3}As_{3} (A=K, Rb, Cs). The molecular-orbital bands emerging from the quasi-degenerate atomic orbitals are exactly solved. An effective Hamiltonian is derived for a region where three partially filled bands intersect the Fermi energy. The deduced local interactions among these active bands show a significant reduction compared to the original atomic interactions. The resulting three-channel Luttinger liquid shows various interaction-induced instabilities including two kinds of spin-triplet superconducting instabilities due to gapless spin excitations, with one of them being superseded by the spin-density-wave phase in the intermediate Hund's coupling regime. The implications of these results for the alkali chromium arsenides are discussed.
authors.affiliation: Condensed Matter Group, Department of Physics, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Hanting
authors.initials: H
authors.lastname: Zhong
authors.affiliation: Condensed Matter Group, Department of Physics, Hangzhou Normal University, Hangzhou 310036, China.|Hangzhou Key Laboratory of Quantum Matter, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Xiao-Yong
authors.initials: XY
authors.lastname: Feng
authors.affiliation: International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.affiliation: Condensed Matter Group, Department of Physics, Hangzhou Normal University, Hangzhou 310036, China.|Hangzhou Key Laboratory of Quantum Matter, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Dai