Tunneling Spectra of a Quasifreestanding Graphene Monolayer

Li, Siyu; Bai, Ke-Ke; Zuo, Wei-Jie; Liu, Yiwen; Fu, Zhong-Qiu; Wang, Wen-xiao; Zhang, Yu; Yin, Long-Jing; Qiao, Jia-Bin; He, Lin

doi:10.1103/physrevapplied.9.054031

Cited by 28 publications

(15 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The interaction between the localized  and  states, which depends on the local configuration of graphene, determines the magnetism of the single-carbon vacancy in graphene 6,8,9,11,12,15,16 . Previously, it was demonstrated that the STM tip can generate an out-of-plane displacement on graphene through a finite Van de Waals force [25][26][27][28] . Here we show that it is possible to generate out-of-plane lattice deformation around the 5 monovacancy and, consequently, tune interactions between the localized  and  states by using the STM tip.…”

mentioning

confidence: 99%

Tunable magnetism of a single-carbon vacancy in graphene

Zhang

Gao

et al. 2020

Science Bulletin

Self Cite

View full text Add to dashboard Cite

Removing a single-carbon vacancy introduces (quasi-)localized states for both  and  electrons in graphene. Interactions between the localized  dangling bond and quasilocalized  electrons of a single-carbon vacancy in graphene are predicted to control its magnetism. However, experimentally confirming this prediction through manipulating the interactions between the  and  electrons remains an outstanding challenge. Here we report the manipulation of magnetism of individual single-carbon vacancy in graphene by using a scanning tunnelling microscopy (STM) tip. Our spin-polarized STM measurements, complemented by density functional theory calculations, indicate that interactions between the localized  and quasilocalized  electrons could split the  electrons into two states with opposite spins even when they are well above the Fermi level. Via the STM tip, we successfully manipulate both the magnitude and direction of magnetic moment of the  electrons with respect to that of the  electrons. Three different magnetic states of the single-carbon vacancy, exhibiting magnetic moments of about 1.6 B, 0.5 B, and 0 B respectively, are realized in our experiment.

show abstract

mentioning

confidence: 99%

Tunable magnetism of a single-carbon vacancy in graphene

Zhang

Gao

et al. 2020

Science Bulletin

Self Cite

View full text Add to dashboard Cite

show abstract

“…In our work, graphene multilayer samples were synthesized on Rhodium foils via a chemical vapor deposition (CVD) method 27,28 . The topmost graphene layer, which electronically decouples from the underlying graphene sheets through the large twist angle, behaves as a free-standing graphene monolayer [29][30][31][32][33] . We carried out STM measurements in defect-free regions to detect intrinsic electronic properties of pristine graphene and the area of a typical defect-free region can reach 110 5 nm 2 (see Fig.…”

mentioning

confidence: 99%

Scanning tunneling microscope study of quantum Hall isospin ferromagnetic states in the zero Landau level in a graphene monolayer

Zhang

Yin

et al. 2019

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

A number of quantum Hall isospin ferromagnetic (QHIFM) states have been predicted in the "relativistic" zero Landau level (LL) of graphene monolayer. These states, especially the states at LL filling factor  = 0 of charge-neutral graphene, have been extensively explored in experiment. To date, identification of these high-field broken-symmetry states has mostly relied on macroscopic transport techniques. Here, we study splitting of the zero LL of graphene at partial filling and demonstrate a direct approach by imaging the QHIFM states at atomic scale with a scanning tunneling microscope. At half filling of the zero LL ( = 0), the system is in a spin unpolarized state and we observe a linear magnetic-fieldscaling of valley splitting. Simultaneously, the spin degeneracy in the two valleys is also lifted by the magnetic fields. When the Fermi level lies inside the spinpolarized states (at  = 1 or -1), the spin splitting is dramatically enhanced because of the strong many-body effects. At  = 0, we direct image the wavefunctions of the QHIFM states at atomic scale and observe an interaction-driven density wave featuring a Kekulé distortion, which is responsible for the large gap at charge neutrality point in high magnetic fields.

show abstract

“…This gap is quite larger than the pure Coulomb gap for a system with comparable size [191], which indicates there is a significant spin splitting of triangulene [186]. The tip-assisted method in this work is also proved to be an effective way to manipulate the structure or property of 2D materials, which is widely used in other researches until now [134,[192][193][194].…”

Section: The Properties Of Triangulene and π-Extended Triangulenementioning

confidence: 77%

“…9(a) and (b). The external magnetic fields quantize the continuous band stucture of graphene into discrete LLs [58,71,[131][132][133][134]. The probing STM tip, acting as a moveable top gate, bends the LLs of the region beneath the tip into the gaps between the LLs of the surrounding regions, which leads to an edge-free GQD beneath the tip with confined orbital states [16,17,22,23,126].…”

Section: Stm Tip-induced Edge-free Gqdsmentioning

confidence: 99%

“…dI/dV -V spectrum on triangulene dimer 1 in the vincinity of the Fermi level shows the conductance steps symmetric around zero bias [Fig. 14(g)], indicating the existence of inelastic excitation [134,211,212]. The excitation threshold was extracted to be about ±14 mV in the IETS spectrum through fitting with the antiferromagnetic spin-1 Heisenberg dimer model [213].…”

Section: The Properties Of Triangulene Dimersmentioning

confidence: 99%

See 1 more Smart Citation

Recent progresses of quantum confinement in graphene quantum dots

2021

Front. Phys.

Self Cite

View full text Add to dashboard Cite

Graphene quantum dots (GQDs) not only have potential applications on spin qubit, but also serve as essential platforms to study the fundamental properties of Dirac fermions, such as Klein tunneling and Berry phase. By now, the study of quantum confinement in GQDs still attract much attention in condensed matter physics. In this article, we review the experimental progresses on quantum confinement in GQDs mainly by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). Here, the GQDs are divided into Klein GQDs, bound-state GQDs and edge-terminated GQDs according to their different confinement strength. Based on the realization of quasi-bound states in Klein GQDs, external perpendicular magnetic field is utilized as a manipulation approach to trigger and control the novel properties by tuning Berry phase and electron-electron (e-e) interaction. The tip-induced edge-free GQDs can serve as an intuitive mean to explore the broken symmetry states at nanoscale and single-electron accuracy, which are expected to be used in studying physical properties of different two-dimensional materials. Moreover, high-spin magnetic ground states are successfully introduced in edge-terminated GQDs by designing and synthesizing triangulene zigzag nanographenes.

show abstract

Tunneling Spectra of a Quasifreestanding Graphene Monolayer

Cited by 28 publications

References 40 publications

Tunable magnetism of a single-carbon vacancy in graphene

Tunable magnetism of a single-carbon vacancy in graphene

Scanning tunneling microscope study of quantum Hall isospin ferromagnetic states in the zero Landau level in a graphene monolayer

Recent progresses of quantum confinement in graphene quantum dots

Contact Info

Product

Resources

About