Rongting’s research work for the Ph.D. degree started from developing a new UHV-VT-Optical-STM system as well as some other related scientific instruments, such as an electron beam evaporator, an improved Pan-type STM scanner etc. Then he used these systems to characterize the spatial configurations, electronic structures and mechanical properties of organic molecules (such as naphthalocyanine) on metal surfaces (such as Ag and Au). His current research interest is mainly focused on utilizing the low-energy electron microscop to study the process of synthesis of films of superconductors and other novel 2D materials. With the real-time microscopy and diffraction LEEM capability, his goal is to grow high-quality superconductor films for transport and other physical property measurements.
(1) Basic physics of condensed states of matter; (2) novel electronic properties including unconventional metallic
Summary of research
Synthesis of graphene on Ir(111) surface
Using CVD methods in a UHV-LEED-VT-STM system, fabricated graphene with 4 rotation angles (R0, R14, R19, R30). Based on the LEED/STM data, proposed a model to summarize and predict different domains of graphene on Ir(111).
• Intercalation of silicon between graphene and Ir(111) surface
Succeeded in intercalating silicon between graphene and Ir(111). LEED and STM data showed that silicon undergoes a √19×√19 reconstruction on Ir(111) surface.
• Formation of buckled silicene on Ir(111)
Fabricated silicene on an Ir(111) substrate. By analyzing the LEED/STM data together with the first-principles calculations, confirmed that this is a (√3×√3) silicene / (√7×√7) Ir(111) configuration and that it has a buckled conformation with 2D continuity.
• Intercalation of hafnium between epitaxial graphene and Ir(111) substrate
• Synthesis of 2D transition metal honeycomb: Hf on Ir(111)
Fabricated a crystalline honeycomb hafnium layers on Ir(111, with a (2×2) superstructure. DFT calculations provided evidence for directional bonding between adjacent Hf atoms.
• Built a UHV-MBE-VT-optical STM system, and used it to analyze spatial, electronic and mechanical properties of naphthalocyanine on metal surfaces
Techniques and skills
• Ambient STM/AFM (DI Multimode AFM)
• Physical Vapor Deposition
• UHV-VTSTM/AFM-LEED-MBE System (Omicron VT)
• Setting up UHV systems
• Setting up a versatile UHV-compatible Leak detector
• Scientific instrument design:
• Developed a versatile Electron-beam evaporator, which has a high heating efficiency and evaporation temperature in excess of 3422℃.
• Developed an improved Pan-type STM scanner，which has a very rigid design and can easily get atomic resolution on HOPG without any damping mechanism.
• Designed a tip-enhanced Raman spectroscopy system, integrated with a homemade UHV-VT-STM
• Software skills: Solid Works, Materials Studio, WSxM, Visual C++, Origin