Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/Si C(0001) by molecular beam epitaxy, which are investigated by scanning ...Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/Si C(0001) by molecular beam epitaxy, which are investigated by scanning tunneling microscopy. The two types of islands distinguished by flat or round tops are revealed, indicating bimodal growth of Fe. The atomic structures on the top surfaces of flat islands are also clearly resolved. Our results may improve the understanding of the mechanisms of metals deposited on graphene and pave the way for future spintronic applications of Fe/graphene systems.展开更多
High-temperature superconductivity(HTSC)remains one of the most challenging and fascinating mysteries in condensed matter physics.Recently,superconductivity with transition temperature exceeding liquid-nitrogen temper...High-temperature superconductivity(HTSC)remains one of the most challenging and fascinating mysteries in condensed matter physics.Recently,superconductivity with transition temperature exceeding liquid-nitrogen temperature is discovered in La_(3)Ni_(2)O_(7) at high pressure,which provides a new platform to explore the unconventional HTSC.In this work,using high-resolution angle-resolved photoemission spectroscopy and ab initio calculation,we systematically investigate the electronic structures of La_(3)Ni_(2)O_(7) at ambient pressure.Our experiments are in nice agreement with ab initio calculations after considering an orbital-dependent band renormalization effect.The strong electron correlation effect pushes a flat band of d_(z^(2))𝑧2 orbital component below the Fermi level(E_(F)),which is predicted to locate right at E_(F) under high pressure.Moreover,the d_(x^(2)−y^(2)) band shows pseudogap-like behavior with suppressed spectral weight and diminished quasiparticle peak near E_(F).Our findings provide important insights into the electronic structure of La_(3)Ni_(2)O_(7),which will shed light on understanding of the unconventional superconductivity in nickelates.展开更多
基金the Ministry of Science and Technology of China (Grant Nos. 2019YFA0308600 and 2020YFA0309000)the National Natural Science Foundation of China (Grant Nos. 92365302, 92065201, 22325203, 92265105, 12074247, and 12174252)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB28000000)the Science and Technology Commission of Shanghai Municipality (Grant Nos. 2019SHZDZX01, 19JC1412701 and 20QA1405100) for financial supportfinancial support from the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302500)。
文摘Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/Si C(0001) by molecular beam epitaxy, which are investigated by scanning tunneling microscopy. The two types of islands distinguished by flat or round tops are revealed, indicating bimodal growth of Fe. The atomic structures on the top surfaces of flat islands are also clearly resolved. Our results may improve the understanding of the mechanisms of metals deposited on graphene and pave the way for future spintronic applications of Fe/graphene systems.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1403100 and 2022YFA1403200)the National Natural Science Foundation of China(Grant Nos.12275148,12004270,and 52272265)+1 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2022B1515120020)support from Tsinghua University Initiative Scientific Research Program.
文摘High-temperature superconductivity(HTSC)remains one of the most challenging and fascinating mysteries in condensed matter physics.Recently,superconductivity with transition temperature exceeding liquid-nitrogen temperature is discovered in La_(3)Ni_(2)O_(7) at high pressure,which provides a new platform to explore the unconventional HTSC.In this work,using high-resolution angle-resolved photoemission spectroscopy and ab initio calculation,we systematically investigate the electronic structures of La_(3)Ni_(2)O_(7) at ambient pressure.Our experiments are in nice agreement with ab initio calculations after considering an orbital-dependent band renormalization effect.The strong electron correlation effect pushes a flat band of d_(z^(2))𝑧2 orbital component below the Fermi level(E_(F)),which is predicted to locate right at E_(F) under high pressure.Moreover,the d_(x^(2)−y^(2)) band shows pseudogap-like behavior with suppressed spectral weight and diminished quasiparticle peak near E_(F).Our findings provide important insights into the electronic structure of La_(3)Ni_(2)O_(7),which will shed light on understanding of the unconventional superconductivity in nickelates.
基金the financial supports from Beijing Natural Science Foundation, China (2172013)the National Key Research and Development Program, China (2016YFB0301101)。
