通过简化的分子束外延法实现多层FeSe薄膜中超导电性的增强
Enhanced Superconductivity in Multilayer FeSe Films by Simplified Molecular Beam Epitaxy
浏览论文内容
中文总结 AI 辅助
本研究开发了一种简化的MBE工艺，无需SrTiO3衬底精细预处理和生长后UHV退火，即可在其上生长出Tc约20 K、厚度14 UC的超导β-FeSe薄膜，实现了超导电性增强。
中文摘要 AI 辅助
在SrTiO3(100)衬底上生长的多单元胞(UC)β-FeSe薄膜因超导转变温度(Tc)相较于块体FeSe显著提升而持续受到关注。此前关于分子束外延(MBE)生长的β-FeSe/SrTiO3(100)的报道中，需采用精细的生长工艺才能实现Tc增强，这使得学界普遍认为SrTiO3衬底的精细预处理及超高真空(UHV)下的生长后退火是必要条件。本研究报告了一种用于在SrTiO3(100)上生长超导多UC β-FeSe薄膜的大幅简化的MBBE工艺，该工艺无需精细的衬底预处理和生长后UHV退火，仍可实现Tc增强。采用适当的覆盖层，厚度为14 UC的外延膜在原位电学输运测量中表现出零电阻转变温度Tc约为20 K。MBE优化过程由薄膜形貌和结构特性随生长参数的变化规律指导，相关特性通过反射高能电子衍射、X射线衍射、原子力显微镜和扫描透射电子显微镜表征。
英文摘要
Multi-unit-cell (UC) \b{eta}-FeSe films grown on SrTiO3(100) continue to attract attention because of the significant enhancement in the superconducting transition temperature (Tc) compared to that in bulk FeSe. In prior reports of molecular beam epitaxy (MBE)-grown \b{eta}-FeSe/SrTiO3(100), elaborate growth protocols have been used to achieve enhanced Tc, leading to a general belief that careful pre-treatment of the SrTiO3 substrate and post-growth annealing in ultrahigh vacuum (UHV) are essential. Here, we report a greatly simplified protocol for the MBE growth of superconducting multi-UC \b{eta}-FeSe films on SrTiO3(100), eliminating the need for careful substrate pre-treatment and post-growth UHV annealing while still achieving an enhanced Tc. With appropriate capping, epitaxial films with 14 UC thickness exhibit a zero-resistance transition temperature Tc ~ 20 K in ex situ electrical transport measurements. The MBE optimization process is guided by the growth-parameter dependencies of film morphology and structural properties, as characterized by reflection high-energy electron diffraction, X-ray diffraction, atomic force microscopy, and scanning transmission electron microscopy.
