Manifestation of Work Function Difference in High Order Gundlach Oscillation

Lin, Chun Liang; Lu, Shin-Ming; Su, Wei-Bin; Shih, H. T.; Wu, Biyi; Yao, Y. D.; Chang, Chia Seng; Tsong, Tien T.

doi:10.1103/physrevlett.99.216103

Cited by 60 publications

(62 citation statements)

References 23 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The subpeaks are most clearly resolved in the second FER of the h-BN. In fact, it has been shown that the energetic position of the second FER is a good measure to determine relative shifts of the surface potential on the local scale, as it is less influenced by the image potential at the sample surface [65]. Inspecting the internal structure of the second FER for the different parts of the h-BN moiré, we find the three peaks being located at ∼6.0, 6.3, and 6.6 V. The subpeak of lowest energy has its maximum intensity at the pore, while the peak of highest energy shows maximum intensity on the wire region, indicating a reduction of the work function when going from the wire to the pore.…”

Section: Resultsmentioning

confidence: 99%

Epitaxial hexagonal boron nitride on Ir(111): A work function template

et al. 2014

View full text Add to dashboard Cite

Hexagonal boron nitride (h-BN) is a prominent member in the growing family of two-dimensional materials with potential applications ranging from being an atomically smooth support for other two-dimensional materials to templating growth of molecular layers. We have studied the structure of monolayer h-BN grown by chemical vapor deposition on Ir(111) by low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) experiments and state-of-the-art density functional theory (DFT) calculations. The lattice mismatch between the h-BN and Ir (111) surface results in the formation of a moiré superstructure with a periodicity of ∼29Å and a corrugation of ∼0.4Å. By measuring the field emission resonances above the h-BN layer, we find a modulation of the work function within the moiré unit cell of ∼0.5 eV. DFT simulations for a 13-on-12 h-BN/Ir(111) unit cell confirm our experimental findings and allow us to relate the change in the work function to the subtle changes in the interaction between boron and nitrogen atoms and the underlying substrate atoms within the moiré unit cell. Hexagonal boron nitride on Ir(111) combines weak topographic corrugation with a strong work function modulation over the moiré unit cell. This makes h-BN/Ir(111) a potential substrate for electronically modulated thin film and heterosandwich structures.

show abstract

Section: Resultsmentioning

confidence: 99%

Epitaxial hexagonal boron nitride on Ir(111): A work function template

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Fortunately, their relative changes in energy and line width are much less affected than absolute values. In particular, relative changes within the 2nd Stark-shifted state are the least affected by the field [10].…”

mentioning

confidence: 97%

“…Surface averaged values of energy, dispersion (and lifetime) of image potential states were extensively probed, first by inverse photoemission (IPES) [7] and later by two-photon photoemission spectroscopy (2PPE) [8]. High spatial resolution of an image potential state was achieved by scanning tunneling spectroscopy (STS) [9,10] . The shifts are consistent with a lateral confinement of the electrons as described by textbook (two-dimensional) particle-in-a-box models [14].…”

mentioning

confidence: 99%

“…Surface averaged values of energy, dispersion (and lifetime) of image potential states were extensively probed, first by inverse photoemission (IPES) [7] and later by two-photon photoemission spectroscopy (2PPE) [8]. High spatial resolution of an image potential state was achieved by scanning tunneling spectroscopy (STS) [9,10] based on the pioneering works of Becker et al [11] and Binnig et al [12]. Such measurements provided information about * Present address: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O.…”

mentioning

confidence: 99%

“…To extract this information, first, the states of all spectra are fitted by Lorentzian functions. We here concentrate on the 2nd image potential state, because it is least affected by the applied external field as mentioned above [10]. Then, the data has to be corrected for the quantum size confinement effects induced by the presence of step edges as described in detail below.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Quantitative determination of a nano-object's atom density without atomic resolution

et al. 2014

View full text Add to dashboard Cite

We outline a possibility to determine the adatom density of individual nano-objects via measurement of their electronic structure. For this aim, the nonlinear shift of image potential states measured on individual Cu nanoclusters on Ag(100) by low-temperature scanning tunneling spectroscopy is carefully analyzed. The quantitative analysis is confirmed by density-functional theory calculations. A peak width analysis furthermore reveals whether the clusters are purely metallic or alloyed. For nanotechnology a structural control on the nanoscale is essential, because the physical as well as chemical properties of nanoscale objects depend on the exact arrangement of their atoms [1]. As a first step, it is of vital importance for scientists and engineers to resolve the internal structure of the nanosystems to understand and, in a subsequent step, tune the resulting macroscopic properties. The atomic structure of nanoparticles can be determined directly by scanning transmission microscopy (STEM) with high resolution down to 50 pm [2], which shows a two-dimensional projection of the crystal in some high-index direction of particles. With STEM, nanoparticles were imaged three dimensionally [3]. Even single defects within nanoparticles were identified recently [4]. Due to the width of the electron beam, the extraction of the data demands sophisticated procedures.For two-dimensional nanoparticles on surfaces, scanning tunneling microscopy (STM) turned out to be a simple and versatile tool for high resolution imaging. However, atomic resolution is often impossible for discrete entities consisting of only a few atoms, in particular for nanoclusters. These objects have the tendency to be moved or restructured at the tunneling parameters necessary for atomic resolution. On the other hand, structural information of a metal surface is clearly reflected in the energetic positions of its image potential states [5,6]. A Rydberg-like series of these states emerges, when an outside charge polarizes a metal surface and is attracted to the induced polarization charge. As the energy levels of these states are pinned to the vacuum level, they are closely related to the work function, which in turn varies with both the chemical composition of the surface and the surface orientation, and thus with atom density. Surface averaged values of energy, dispersion (and lifetime) of image potential states were extensively probed, first by inverse photoemission (IPES) [7] and later by two-photon photoemission spectroscopy (2PPE) [8]. High spatial resolution of an image potential state was achieved by scanning tunneling spectroscopy (STS) [9,10] . The shifts are consistent with a lateral confinement of the electrons as described by textbook (two-dimensional) particle-in-a-box models [14]. Such an assignment assumes atomically flat islands with perfect coordination, though a relation to potential relaxation or reconstruction of the latter has not been made so far [16]. In this article, we present a method for the analysis of metallic nanostructures ...

show abstract

Vortex‐Oriented Ferroelectric Domains in SnTe/PbTe Monolayer Lateral Heterostructures

Chang

Villanova

et al. 2021

Advanced Materials

View full text Add to dashboard Cite

Heterostructures formed from interfaces between materials with complementary properties often display unconventional physics. Of especial interest are heterostructures formed with ferroelectric materials. These are mostly formed by combining thin layers in vertical stacks. Here the first in situ molecular beam epitaxial growth and scanning tunneling microscopy characterization of atomically sharp lateral heterostructures between a ferroelectric SnTe monolayer and a paraelectric PbTe monolayer are reported. The bias voltage dependence of the apparent heights of SnTe and PbTe monolayers, which are closely related to the type‐II band alignment of the heterostructure, is investigated. Remarkably, it is discovered that the ferroelectric domains in the SnTe surrounding a PbTe core form either clockwise or counterclockwise vortex‐oriented quadrant configurations. In addition, when there is a finite angle between the polarization and the interface, the perpendicular component of the polarization always points from SnTe to PbTe. Supported by first‐principles calculation, the mechanism of vortex formation and preferred polarization direction is identified in the interaction between the polarization, the space charge, and the strain effect at the horizontal heterointerface. The studies bring the application of 2D group‐IV monochalcogenides on in‐plane ferroelectric heterostructures a step closer.

show abstract

Manifestation of Work Function Difference in High Order Gundlach Oscillation

Cited by 60 publications

References 23 publications

Epitaxial hexagonal boron nitride on Ir(111): A work function template

Epitaxial hexagonal boron nitride on Ir(111): A work function template

Quantitative determination of a nano-object's atom density without atomic resolution

Vortex‐Oriented Ferroelectric Domains in SnTe/PbTe Monolayer Lateral Heterostructures

Contact Info

Product

Resources

About