RHK PanScan

News & Events

Panscan Freedom SPM,  VT Beetle
Events
Event Date: September 25, 2017

September 25-29 Suzhou, China
NC-AFM 2017
The Conference will be held at the Garden Hotel Suzhou in Suzhou, China

+Show More
Panscan Freedom SPM,  VT Beetle
Events
Event Date: September 24, 2017

September 24 – 29 Montpellier, France
European Conference on Applications of Surface and Interface Analysis
The Conference will be held at Le CORUM, Esplanade Charles De Gaulle BP 2220 34000 Montpellier
http://www.ecasia2017.com/

+Show More
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.

+Show More
PRIcon
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

+Show More