Superconductivity of InN caused by In-In nano-structure

• Published in: Physica status solidi. C Vol. 4; no. 2; pp. 660 - 663
• Main Author: Inushima, Takashi
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.02.2007; WILEY‐VCH Verlag
• Subjects: 72.80.Ey; 74.25.Fy; 74.90.+n
• ISSN: 1862-6351; 1610-1642
• DOI: 10.1002/pssc.200673228

There is an optimum carrier density for the occurrence of the superconductivity in n‐type InN. The lowest carrier density is limited by the Mott transition of ne ∼ 2 × 1017 cm–3 and the highest density is limited by the superconductivity to metal transition of ne ∼ 5 × 1020 cm–3. Between these carrier densities, InN shows superconductivity and vortex motion is a current tunneling through micro Josephson‐junctions. A mechanism is proposed where the occurrence of the superconductivity is related to the presence of two u ‐parameters of 3/8 and 5/8, which causes In‐In chains of finite length in the ab plane. The In‐In chains, which originate from the In‐In nano‐structure elongating along [11$ \bar 2 $0], are coupled to form micro Josephsonjunctions. A possibility of nano‐structure instability is suggested by the temperature dependence of the u ‐parameter obtained by molecular dynamics calculations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)