Characterization of external potential for field emission resonances and its applications on nanometer-scale measurements

Abstract

The form of the external potential (FEP) for generating field emission resonance (FER) in a scanning tunneling microscopy (STM) junction is usually assumed to be triangular. We demonstrate that this assumption can be examined using a plot that can characterize FEP. The plot is FER energies versus the corresponding distances between the tip and sample. Through this energy-distance relationship, we discover that the FEP is nearly triangular for a blunt STM tip. However, the assumption of a triangular potential form is invalid for a sharp tip. The disparity becomes more severe as the tip is sharper. We demonstrate that the energy-distance plot can be exploited to determine the barrier width in field emission and estimate the effective sharpness of an STM tip. Because FERs were observed on Pb islands grown on the Cu(111) surface in this study, determination of the tip sharpness enabled the derivation of the subtle expansion deformation of Pb islands due to electrostatic force in the STM junction.

Observing quantum trapping on MoS2 through the lifetimes of resonant electrons: revealing the Pauli exclusion principle

“…Recent studies have explained that under the same current, more FERs result from a sharper STM tip. [22][23][24] Fig. 1(b) also shows that the higher-order peaks in the spectra with three and ve FERs are all much narrower than those in the spectra with four and six FERs.…”

“…S2 †). 34 On the contrary, the linewidth modulation vanishes on Ag(111) without a band gap above the vacuum level (see ESI note 3, Fig 24 According to electrostatics, the electric eld in an STM junction is not constant due to the tip structure similar to that in This journal is © The Royal Society of Chemistry 2020…”

“…21 The zero valley intensities appearing around the FER may indicate that the observed material has a band gap above the vacuum level. 21 The number of FERs can manifest the sharpness [22][23][24] and eld enhancement factor 25 of the STM tip. Previous studies have demonstrated that FER can be used to investigate the atomic structure of an insulator, 26 plasmon-assisted electron tunneling, 27 and the dynamics 28,29 and lateral quantization [30][31][32] of surface electrons above the vacuum level.…”

Noise Modeling in Field Emission and Evaluation of the Nano-Receiver in Terms of Temperature

“…Our measurement results and the obtained theoretical model describe the same behavior. Therefore, it can be stated that the probability density of the field-emission current is accurately modeled by ( 7), (8), and (10).…”

Probing tip-induced attractive deformation of graphite surfaces through wave function dissipation in field emission resonance

“…Consequently, FER has been a versatile technique to explore various phenomena . For example, the FER number can reflect the sharpness of an STM tip; a higher FER number indicates a sharper tip [17,35,36]. In addition, previous studies demonstrated that the FER observed on the reconstructed surfaces revealed spatial variation in linewidth [32][33][34].…”