Uchida Masaki, Nomoto Takuya, Musashi Maki, Arita Ryotaro, Kawasaki Masashi
Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan.
Phys Rev Lett. 2020 Oct 2;125(14):147001. doi: 10.1103/PhysRevLett.125.147001.
We report on strain engineering of superconductivity in RuO_{2} single-crystal films, which are epitaxially grown on rutile TiO_{2} and MgF_{2} substrates with various crystal orientations. Systematic mappings between the superconducting transition temperature and the lattice parameters reveal that shortening of specific ruthenium-oxygen bonds is a common feature among the superconducting RuO_{2} films. Ab initio calculations of electronic and phononic structures for the strained RuO_{2} films suggest the importance of soft phonon modes for emergence of the superconductivity. The findings indicate that simple transition metal oxides such as those with a rutile structure may be suitable for further exploring superconductivity by controlling phonon modes through the epitaxial strain.
我们报道了在二氧化钌（RuO₂）单晶薄膜中进行超导应变工程的研究，这些薄膜是在具有不同晶体取向的金红石型二氧化钛（TiO₂）和氟化镁（MgF₂）衬底上外延生长的。超导转变温度与晶格参数之间的系统映射表明，特定钌 - 氧键的缩短是超导RuO₂薄膜的一个共同特征。对应变RuO₂薄膜的电子和声子结构进行的从头算计算表明，软声子模式对于超导的出现很重要。这些发现表明，诸如具有金红石结构的那些简单过渡金属氧化物可能适合通过外延应变控制声子模式来进一步探索超导性。
