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Solid-state electrical conducting materials can be roughly categorized as superconductors, conductors, and semiconductors, depending on their conducting carriers, resistance, and band structures. This research reports the discovery of super-semiconductors, whose resistivity is 3–10 orders of magnitude lower than conventional semiconductors at room temperature. In addition, there is a transition from a metal state to a super-semiconducting state at near room temperatures, which is accompanied by an increase in hole carrier density and the mobility increase in electrons. For the first time, a hole-dominated carrier metal is observed in nanostructured bimetallic arrays near room temperature, and no other special conditions are required. Such a behavior is due to the generation of hot electrons and holes induced by metal plasmon resonance in the infrared range in the nanostructured bimetallic arrays. Our research empowers metals with semiconductor features and paves the way to realize ultra-low-power metal-based semiconductor devices. [ABSTRACT FROM AUTHOR]

• The correlation between structures and the T c in FeSe-family is presented for the first time. • The distorted FeSe 4 tetrahedron plays an important role in understanding the superconductivity. • The electronic correlation and FS nesting between electron pockets are associated with distorted FeSe 4 tetrahedron. • The crystal structure of N 0.81(1) D 3.24(2) Fe 2 Se 2 is determined by neutron and x-ray powder diffraction. We demonstrate that unique cation, ND 4 (1−δ)+, exists between FeSe layers and induces a large distortion of the FeSe 4 tetrahedron in N 0.81(1) D 3.24(2) Fe 2 Se 2 by neutron and X-ray powder diffraction. The electronic correlations of the Fe 3d electrons and Fe d xy , d yz and d xz band widths could be tuned by changing the FeSe 4 tetrahedron distortion, revealing the importance of lattice distortion to the superconductivity of FeSe-based intercalates. [ABSTRACT FROM AUTHOR]