Single and multi domain buckled germanene phases on Al(111)surface

作     者：Dmitriy A.Muzychenko Sergey I.Oreshkin Vladimir I.Panov Chris Van Haesendonck Andrey I.Oreshkin 

作者机构：Faculty of PhysicsLomonosov Moscow State University119991 MoscowRussia Sternberg Astronomical InstituteLomonosov Moscow State University119234 MoscowRussia Solid-State Physics and Magnetism SectionKU LeuvenBE-3001 LeuvenBelgium 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2019年第12卷第12期

页      面：2988-2996页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported Russian Foundation for Basic Research(RFBR) by the computing facilities of the M.V.Lomonosov Moscow State University(MSU)Research Computing Center supported by the Research Foundation–Flanders(FWO,Belgium) 

主　　题：germanene two-dimensional(2D)materials scanning tunneling microscopy density functional theory aluminum 

摘      要：The simultaneous formati on of single domain(3×3)and multi domai n(√7×√7)R(±19.1°)germa nene phases on Al(111)surface in thesub-monolayer range was studied using seanning tunneling microscopy(STM)and density functional theory(DFT)based *** results revealed that both germa nene phases nu cleate and grow in dependently from each other and regardless of Al substratetemperature within significantly expanded range Ts=27-200℃.Our results unambiguously showed that STM images with hexagonalcontrast yield correct-resolved structure for both germanene phases,while honeycomb contrast is a result of an artificial tip-induced STM ***-principles calculations suggested atomic models with strongly buckled germanene(2×2)/Al(111)(3×3)and(√3×√3)R30°/Al(111)(√7×√7)R(±19.1°)with one of eight and one of six Ge atoms protruding upward respectively,that consistently describe the experimentally observed STM images both for single and multi domai n surface *** to the DFT based simulati ons both germa nene(2×2)and(√3×√3)R30°superstructures have a stretched lattice strain with respect to the ideal free-standing germa nene by 6.2%and 13.9%,***,numerous small domains separated by domain boundaries in the(√3×√3)R30°/Al(111)(√7×√7)R(±19.1°)germanenephase tend to reduce the surface energy and prevent the formation of extended single domains,in contrast to the(2×2)/Al(111)(3×3)***,our experimental results showed that the nucleation and growth of germa nene on Al(111)surface yield strong modifications of Alsurface even at room temperature(RT),which may be contributed to the formation of Al-Ge alloy due to Ge surface solid-states reactivitythat was ignored in recent *** is already evident from our present findings that the role of Al atoms in the formation of(3×3)and(√7×√7)R(±19.1°)germa nene phases is worthy to be carefully studied in the future,which could be an important knowledge for large-quantityfabrication of germane