RHK PanScan

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Panscan Freedom SPM,  VT Beetle
News
Posted Date: September 5, 2017

Small Business Innovation Research Program Provides Seed Funding for R&D

RHK Technology has been awarded a National Science Foundation (NSF) Small Business Technology Transfer (STTR) grant, in conjunction with Prof. Gang-yu Liu at University of California, Davis and Prof. Darrin Hanna at Oakland University, to conduct research and development work on a smart and fast SPM controller and microscope add-on for automatically finding dynamic features, scanning them at ultra-high-speed scan rates, and providing true material mechanical properties.  These achievements will expand AFM significantly, especially in the fields of nanodevice inspection and quality control, nanolithography, tissue engineering, and development of nanomaterials; an exciting leap forward.  With designing the microscope add-on proposed in this work to fit existing microscopes, thousands of scientists will have the option to utilize smart and fast scanning with their existing equipment.  The features provided in this smart and fast AFM will add important capabilities for imaging and characterization that will be used by professionals dedicated to engineering the future in research and development institutions and departments worldwide.

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Image of the Month
Posted Date: September 4, 2017

Reference:
Scientific Reports 7 (2017): 43214

Figure 3. STM images of quasi-freestanding WSe2 islands. (a) STM image of 90 × 75 Å2 area of elevated
1 ML island obtained at 2 V sample bias. (b) Image of the same area at 3 V bias. (c) Cross-section of type-B (multi-ring) pattern from (a). (d) Cross-section of type-A (single-ring) pattern from (a). The STM cross- sections are oriented perpendicular to atomic rows, and the horizontal axes are normalized to a0. The central minima in (c,d) have slightly different shapes due to different contributions of cosine modes (see Discussion part and Supplementary Note 2). (e) The larger scale, 260 × 260 Å2, STM image of phonon interference patterns on elevated 1 ML island. The image uses gradient contrast. One of type-B and one of type-A patterns are schematically surrounded by dotted lines. For gradient contrast, the missing half-rings are less visible. Bright- contrast features originate from residual contaminating particles. (Left inset) The left inset shows different absorption sites for defects, H-site vs. TM-site, that may also cause type-A vs. type-B standing wave patterns. (Right inset) STM image in the right inset clarifies the horizontal axis units in (c,d) and the orientation of crystal axes in (a,b,e). The pattern on this STM image (surrounded by dotted line type-C pattern) only contains a broad central minimum.

Figure 3. STM images of quasi-freestanding WSe2 islands. (a) STM image of 90 × 75 Å2 area of elevated
1 ML island obtained at 2 V sample bias. (b) Image of the same area at 3 V bias. (c) Cross-section of type-B (multi-ring) pattern from (a). (d) Cross-section of type-A (single-ring) pattern from (a). The STM cross- sections are oriented perpendicular to atomic rows, and the horizontal axes are normalized to a0. The central minima in (c,d) have slightly different shapes due to different contributions of cosine modes (see Discussion part and Supplementary Note 2). (e) The larger scale, 260 × 260 Å2, STM image of phonon interference patterns on elevated 1 ML island. The image uses gradient contrast. One of type-B and one of type-A patterns are schematically surrounded by dotted lines. For gradient contrast, the missing half-rings are less visible. Bright- contrast features originate from residual contaminating particles. (Left inset) The left inset shows different absorption sites for defects, H-site vs. TM-site, that may also cause type-A vs. type-B standing wave patterns. (Right inset) STM image in the right inset clarifies the horizontal axis units in (c,d) and the orientation of crystal axes in (a,b,e). The pattern on this STM image (surrounded by dotted line type-C pattern) only contains a broad central minimum.

Abstract
Using quantum tunneling of electrons into vibrating surface atoms, phonon oscillations can be observed on the atomic scale. Phonon interference patterns with unusually large signal amplitudes have been revealed by scanning tunneling microscopy in intercalated van der Waals heterostructures. Our results show that the effective radius of these phonon quasi-bound states, the real-space distribution of phonon standing wave amplitudes, the scattering phase shifts, and the nonlinear intermode coupling strongly depend on the presence of defect-induced scattering resonance. The observed coherence of these quasi-bound states most likely arises from phase- and frequency-synchronized dynamics of
all phonon modes, and indicates the formation of many-body condensate of optical phonons around resonant defects. We found that increasing the strength of the scattering resonance causes the increase of the condensate droplet radius without affecting the condensate fraction inside it. The condensate can be observed at room temperature.

Reference:
Scientific Reports 7 (2017): 43214

Credits:
Igor Altfeder1, Andrey A. Voevodin1,2, Michael H. Check1, Sarah M. Eichfeld3, Joshua A. Robinson3 & Alexander V. Balatsky4,5

1Nanoelectronic Materials Branch, Air Force Research Laboratory, Wright Patterson AFB, OH 45433, USA.
2Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, USA.
3Department of Materials Science and Engineering and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA 16802, USA.
4Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
5Nordita, Center for Quantum Materials, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, 10691 Stockholm, Sweden. Correspondence and requests for materials should be addressed to I.A. (email: [email protected])

Microscope:
UHV Beetle 300 STM

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Panscan Freedom SPM,  VT Beetle
Events
Event Date: August 29, 2017

Beijing, China
August 29 – August 31.
http://www.chinanano.org/
Booths 505-507

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Image of the Month
Posted Date: August 1, 2017

Reference:
Scientific reports 7 (2017): 43451.

Figure 2. Scanning tunneling microscopy of the Graphene-Ice-Mica interface. (a) UHV STM topography (190 × 190 nm2) of a few layers graphene deposited on mica recorded at 0.2 V and 100 pA. Ice crystals (darker regions) are observed intercalated between graphene and mica surrounded by two water layers (brighter region). (b) A high resolution image (17 × 17 nm2) at the edges between an ice crystal and two water layers. A ripple-like structure is observed. (c) An atomic resolution image (6 × 6 nm2) clearly showing the ripple-like structure of graphene. (d) FFT of the hills (red circle in panel (c)) and valleys (green circle in panel (c)) of the rippled graphene surface and the higher edges of the fractal (blue circle in panel (b)).

Figure 2. Scanning tunneling microscopy of the Graphene-Ice-Mica interface. (a) UHV STM topography (190 × 190 nm2) of a few layers graphene deposited on mica recorded at 0.2 V and 100 pA. Ice crystals (darker regions) are observed intercalated between graphene and mica surrounded by two water layers (brighter region). (b) A high resolution image (17 × 17 nm2) at the edges between an ice crystal and two water layers. A ripple-like structure is observed. (c) An atomic resolution image (6 × 6 nm2) clearly showing the ripple-like structure of graphene. (d) FFT of the hills (red circle in panel (c)) and valleys (green circle in panel (c)) of the rippled graphene surface and the higher edges of the fractal (blue circle in panel (b)).

Abstract
The distribution of potassium (K+) ions on air-cleaved mica is important in many interfacial phenomena such as crystal growth, self-assembly and charge transfer on mica. However, due to experimental limitations to nondestructively probe single ions and ionic domains, their exact lateral organization
is yet unknown. We show, by the use of graphene as an ultra-thin protective coating and scanning probe microscopies, that single potassium ions form ordered structures that are covered by an ice layer. The K+ ions prefer to minimize the number of nearest neighbour K+ ions by forming row-like structures as well as small domains. This trend is a result of repulsive ionic forces between adjacent ions, weakened due to screening by the surrounding water molecules. Using high resolution conductive atomic force microscopy maps, the local conductance of the graphene is measured, revealing a direct correlation between the K+ distribution and the structure of the ice layer. Our results shed light on the local distribution of ions on the air-cleaved mica, solving a long-standing enigma. They also provide a detailed understanding of charge transfer from the ionic domains towards graphene.

Reference:
Scientific reports 7 (2017): 43451.

Credits:
Pantelis Bampoulis1,2,*, Kai Sotthewes1,*, Martin H. Siekman1, Harold J. W. Zandvliet1 & Bene Poelsema1

1Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands.
2Physics of Fluids and J.M. Burgers Centre for Fluid Mechanics, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands.
*These authors contributed equally to this work. Correspondence and requests for materials should be addressed to P.B. (email: [email protected])

Microscope:
UHV Beetle 3000 STM

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