Moiré patterns on STM images of graphite induced by rotations of surface and subsurface layers

Flores, Marcos; Cisternas, Eduardo; Correa, J.D.; Vargas, P.

doi:10.1016/j.chemphys.2013.06.022

Cited by 41 publications

(30 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Scanning Tunnelling Microscopy (STM), the surface electronic states can be affected by the presence of subsurface features. 6,7,8 In Electric Force Microscopy (EFM), charges located below the surface can similarly influence the electrostatic force or the surface displacement sensed by the tip. 9,10,11 Finally, in Scanning Thermal Microscopy (SThM), the thermal dissipation depends to a great extent on a given volume located under the tip and any non-homogeneity can be thus probed.…”

Section: Introductionmentioning

confidence: 99%

Subsurface imaging of two-dimensional materials at the nanoscale

et al. 2017

View full text Add to dashboard Cite

Scanning probe Microscopy (SPM) represents a powerful tool that, in the past thirty years, has allowed one to investigate material surfaces in unprecedented ways at the nanoscale level. However, SPM has shown very little power of depth penetration, whereas several nanotechnology applications would require it. Subsurface imaging has been achieved only in a few cases, when subsurface features influence the physical properties of the surface, such as the electronic states or the heat transfer. Ultrasonic Force Microscopy (UFM), an adaption of the Atomic Force Microscopy (AFM) contact mode, can dynamically measure the stiffness of the elastic contact between the probing tip and the sample surface. In particular, UFM has proven highly sensitive to the near-surface elastic field in non-homogeneous samples.In this paper, we present an investigation of two-dimensional (2D) materials, namely flakes of graphite and molybdenum disulphide placed on structured polymeric substrates.We show that UFM can non-destructively distinguish suspended and supported areas and localize defects, such as buckling or delamination of adjacent monolayers, generated by residual stress. Specifically, UFM can probe small variations in the local indentation induced by the mechanical interaction between tip and sample. Therefore, any change in the elastic modulus within the volume perturbed by the applied load or the flexural bending of the suspended areas can be detected and imaged. Such a power of investigation is very promising in order to investigate the buried interfaces of nanostructured 2D materials such as in graphene-based devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Subsurface imaging of two-dimensional materials at the nanoscale

et al. 2017

View full text Add to dashboard Cite

show abstract

“…An efficient approach to generate graphene superlattices is to utilize the periodic potential of the substrate, e.g where monolayer graphene may be placed on top of graphite or hexagonal boron nitride [11][12][13][14][15][16][17] . Graphite, a typical stacked layer material, has a distinct anisotropy, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it is very common to observe moiré patterns on highly oriented pyrolytic graphite (HOPG) surfaces by scanning tunneling microscopy (STM). [14][15][16][17][18][19][20][21][22] The moiré pattern can also be understood electronically as a superperiodic interference structure: a superlattice, with periods typically in the range of tens of nanometers, akin to the optical interference patterns typically associated with moiré interference. The observed superlattices are largely associated with native defects produced during the graphite growth or subsequent annealing treatment.…”

Section: Introductionmentioning

confidence: 99%

Liquid-assisted tip manipulation: fabrication of twisted bilayer graphene superlattices on HOPG

et al. 2015

View full text Add to dashboard Cite

We use the tip of a scanning tunneling microscope (STM) to manipulate single weakly bound nanometer-sized sheets on a highly oriented pyrolytic graphite (HOPG) surface through artificially increasing the tip and sample interaction by pretreatment of the surface using a liquid thiol molecule. By this means it is possible to tear apart a graphite sheet against a step and fold this part onto the HOPG surface and thus generate graphene superlattices with hexagonal symmetry. The tip and sample surface interactions, including the van der Waals force, electrostatic force and capillary attraction force originating from the Laplace pressure due to the formation of a highly curved fluid meniscus connecting the tip and sample, are discussed quantitatively to understand the formation mechanism of a graphene superlattice induced by the STM tip. The capillary force plays a key role in manipulating the graphite surface sheet under humid conditions. Our approach provides a simple and feasible route to prepare controllable superlattices and graphene nanoribbons and also to better understand the process of generation of a graphene superlattice on the surface of HOPG with the tip.

show abstract

“…[14][15][16][17][18] Scanning tunneling microscopy and spectroscopy (STM/STS) are ideal tools for investigating such effects as they can be used to resolve the interaction between morphology and electronic structure at the atomic scale, as has been demonstrated for twisted bilayer graphene. 12,13,[19][20][21] The heterojunction of twisted MoS 2 deposited on graphene or graphite is also noteworthy. The band profile and morphology have been revealed in previous STM/STS investigations, [22][23][24][25][26] and the opening of a band gap in graphene by overlaying a MoS 2 monolayer has been observed using angle-resolved photoemission spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Moiré-related in-gap states in a twisted MoS2/graphite heterojunction

Butler

Huang

et al. 2017

npj 2D Mater Appl

View full text Add to dashboard Cite

This report presents a series of low-temperature (4.5 K) scanning tunneling microscopy and spectroscopy experimental results on monolayer MoS 2 deposited on highly oriented pyrolytic graphite using chemical vapor deposition. To reveal the detailed connection between atomic morphology and conductivity in twisted MoS 2 /graphite heterojunctions, we employ high-sensitivity tunneling spectroscopy measurements by choosing a reduced tip-sample distance. We discern previously unobserved conductance peaks within the band gap range of MoS 2 , and by comparing the tunneling spectra from MoS 2 grains of varying rotation with respect to the substrate, show that these features have small but non-negligible dependence on the moiré superstructure. Furthermore, within a single moiré supercell, atomically resolved tunneling spectroscopy measurements show that the spectra between the moiré high and low areas are also distinct. These in-gap states are shown to have an energy shift attributed to their local lattice strain, matching corresponding behavior of the conduction band edge, and we therefore infer that these features are intrinsic to the density of states, rather than experimental artifacts, and attribute them to the twisted stacking and local strain energy of the MoS 2 /graphite heterointerface.

show abstract

Moiré patterns on STM images of graphite induced by rotations of surface and subsurface layers

Cited by 41 publications

References 35 publications

Subsurface imaging of two-dimensional materials at the nanoscale

Subsurface imaging of two-dimensional materials at the nanoscale

Liquid-assisted tip manipulation: fabrication of twisted bilayer graphene superlattices on HOPG

Moiré-related in-gap states in a twisted MoS2/graphite heterojunction

Contact Info

Product

Resources

About