Zero modes on zero-angle grain boundaries in graphene

Phillips, Madeleine; Mele, E. J.

doi:10.1103/physrevb.91.125404

Cited by 13 publications

(14 citation statements)

References 22 publications

(38 reference statements)

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“…Similar band projection analysis has been used to study edge states in graphene grain boundaries. 60 For the zigzag case, the bands are folded along the horizontal k x -axis in Fig. 1…”

Section: Tight-binding Descriptionmentioning

confidence: 99%

Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform

2019

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We study in-plane lateral heterostructures of commensurate transition-metal dichalcogenides, such as MoS2-WS2 and MoSe2-WSe2, and find interfacial and edge states that are highly localized to these regions of the heterostructure. These are one-dimensional (1D) in nature, lying within the bandgap of the bulk structure and exhibiting complex orbital and spin structure. We describe such heteroribbons with a three-orbital tight-binding model that uses first principles and experimental parameters as input, allowing us to model realistic systems. Analytical modeling for the 1D interfacial bands results in long-range hoppings due to the hybridization along the interface, with strong spin-orbit couplings. We further explore the Ruderman-Kittel-Kasuya-Yosida indirect interaction between magnetic impurities located at the interface. The unusual features of the interface states result in effective long-range exchange non-collinear interactions between impurities. These results suggest that transition-metal dichalcogenide interfaces could serve as stable, tunable 1D platform with unique properties for possible use in exploring Majorana fermions, plasma excitations and spintronics applications.

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“…Similar band projection analysis has been used to study edge states in graphene grain boundaries. 60 For the zigzag case, the bands are folded along the horizontal k x -axis in Fig. 1…”

Section: Tight-binding Descriptionmentioning

confidence: 99%

Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform

2019

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“…One particular type of polycrystalline graphene, as learned from electrons, is the extended line defect containing carbon atom pentagons and octagons. Many peculiar electronic characteristics have been explored theoretically due to the unique structure of this defect [8,9,10,11,12,13] Furthermore, such extended linear defect has been experimentally observed on a graphene layer grown on a metallic substrate [14]. The line defect has important applications in valleytronics.…”

Section: Introductionmentioning

confidence: 99%

Controllable valley filter in graphene topological line defect with magnetic field

Tian

Ren

Zhou

et al. 2020

Preprint

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The extended line defect of graphene is an extraordinary candidate in valleytronics while the high valley polarization can only occur for electrons with high incidence angles which brings about tremendous challenges to experimental realization. In this paper, we propose a simple scheme to filter one conical valley state by applying a local magnetic field. It is found that due to the movement of the Dirac points, the transmission profiles of the two valleys are shifted along the injection-angle axis at the same pace, resulting in the peak transmission of one valley state being reduced drastically while remaining unaffected for the other valley state, which induces nearly perfect valley polarization. This scheme can be easily implemented in experiments and plays a key role in graphene valleytronics.

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“…Analogously, graphene functionalized with sp 3 defects, such as atomic hydrogen, is also predicted to host zero modes with an individual electron, forming thereby a S = 1/2 defect 16,25 . Some graphene grain boundaries are also predicted to host zero modes and local moments 22,29,35,38 , as well as some interfaces between ribbons of different width 43,46 .…”

Section: Introductionmentioning

confidence: 99%

Probing local moments in nanographenes with electron tunneling spectroscopy

Ortiz,

Fernández-Rossier

2020

Preprint

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The emergence of local moments in graphene zigzag edges, grain boundaries, vacancies and sp 3 defects has been widely studied theoretically. However, conclusive experimental evidence is scarce. Recent progress in on-surface synthesis has made it possible to create nanographenes, such as triangulenes, with local moments in their ground states, and to probe them using scanning tunneling microscope (STM) spectroscopy. Here we review the application of the theory of sequential and cotunneling transport to relate the dI/dV spectra with the spin properties of nanographenes probed by STM. This approach permits us to connect the dI/dV with the many-body energies and wavefunctions of the graphene nanostructures. We apply this method describing the electronic states of the nanographenes by means of exact diagonalization of the Hubbard model within a restricted Active Space. This permits us to provide a proper quantum description of the emergence of local moments in graphene and its interplay with transport. We discuss the results of this theory in the case of diradical nanographenes, such as triangulene, rectangular ribbons and the Clar's goblet, that have been recently studied experimentally by means of STM spectroscopy. This approach permits us to calculate both the dI/dV spectra, that yields excitation energies, as well as the atomically resolved conductivity maps, that provide information on the wavefunctions of the collective spin modes.

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Zero modes on zero-angle grain boundaries in graphene

Cited by 13 publications

References 22 publications

Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform

Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform

Controllable valley filter in graphene topological line defect with magnetic field

Probing local moments in nanographenes with electron tunneling spectroscopy

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