Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session R60: Advances in Scanned Probe Microscopy IFocus Live
|
Hide Abstracts |
Sponsoring Units: GIMS Chair: Laurel Winter, Los Alamos National Laboratory |
Thursday, March 18, 2021 8:00AM - 8:36AM Live |
R60.00001: Direct and converse flexoelectricity: the effect of strain and electric field gradients on nanoscale electromechanical responses Invited Speaker: Neus Domingo Surface electromechanics at the nanoscale are typically studied by Piezoresponse Force Microscopy (PFM), based on the inverse piezoelectric effect. As a first approach, generally only homogeneous responses are taken into account, but it has been realized that the effect of gradients in electro-mechanical phenomena at the nanoscale can become dominating: the generation of electrical signals after the application of mechanical strain gradients with an AFM tip has been proved, and it has been shown that it is possible to write ferroelectric domains [1] or to move oxygen vacancies and charges. |
Thursday, March 18, 2021 8:36AM - 9:12AM Live |
R60.00002: Time-Resolved Scanning Probe Techniques Invited Speaker: Lukas Eng N/A |
Thursday, March 18, 2021 9:12AM - 9:24AM Live |
R60.00003: A Mach-Zehnder interferometer based tuning fork microwave impedance microscope ZHIFU LIU, Patrick Krantz, Kevin Michael Ryan, Venkat Chandrasekhar The scanning microwave impedance microscope (MIM) makes available a non-contact means of determining the electrical properties of structures with high resolution [1, 2]. Commercial MIMs are used to detect defects in devices not easily seen by other means [3]. MIM is also a powerful probe for fundamental studies of new phenomena [4, 5]. Here we report a MIM setup based on a Mach-Zehnder interferometer through a home-built probe/tuning fork/PCB board configuration [6]. The setup is sensitive to small conductivity variations in the sample through the admittance modulation between the probe tip and the sample. The setup takes advantages of the large dynamic range of scattering matrix parameters of the microwave resonance, impedance matching condition for better tunability with broadband microwave frequency. Features of buried conducting and insulating structures can be measured. We discuss our setup as well as the sources and reduction of the noise. |
Thursday, March 18, 2021 9:24AM - 9:36AM Live |
R60.00004: Near-field infrared nanospectroscopy of insulating and metallic SrTiO3 Haoyue Jiang, David Lahneman, Patrick McArdle, Muhammad M Qazilbash, Amlan Biswas, Yasin C. Durmaz, Fritz Keilmann Scattering-type, scanning near-field infrared nanospectroscopy is a powerful tool for exploring nanoscale properties of materials that are not easily accessible by conventional far-field techniques. For example, one can resolve optical constants of thin surface layers and probe light-matter excitations such as propagating surface-phonon polaritons (SPhPs). Experimental spectra in the infrared and terahertz range have been obtained on the surface metallic layer of insulating strontium titanate (SrTiO3) crystals. The surface metallicity is due to oxygen deficiencies induced by vacuum annealing. The spectra are modeled with full-wave numerical simulations taking into account the full geometry of the experimental probe. Hence, we extract the dynamical properties of the free charge carriers in the metallic layer. Additionally, we experimentally obtain hyperspectral line scans mapping the interference of SPhPs launched from the probe tip and from a gold edge on the insulating surface of pristine SrTiO3. Our full-wave numerical method is used for modeling of the experimental data to obtain the properties of the SPhPs. |
Thursday, March 18, 2021 9:36AM - 9:48AM Live |
R60.00005: A new compact closed-cycle cryocooler system for variable temperature nano-imaging and -spectroscopy Kathryn Hasz, Sven A Doenges, Kyoung-Duck Park, Tao Jiang, Fabian Menges, Markus Raschke Scanning nano-optical imaging and -spectroscopy have emerged as powerful tools in investigating and understanding heterogeneities and associated physics in a wide range of organic, layered van der Waals, and correlated electron materials. However, to answer many fundamental questions and to access complex quantum phases requires cryogenic temperatures. Despite this need, the extension of optical nano-imaging to variable and low temperatures has remained a major experimental challenge. Here, we present from variable temperature infrared nano-imaging and spectroscopy (IR s-SNOM) to tip-enhanced photoluminescence and nano-Raman spectroscopy in different instruments based on closed cycle cryocoolers with an exchange gas cooled low vibration interface. At the example of surface plasmon polariton (SPP) nano-imaging of graphene, we establish IR nano-imaging at temperatures as low as 15 K with spatial resolution of 10 nm allowing us to access the fundamental limits of SPP propagation. Further, we demonstrate low-temperature TEPL and TERS of transition metal dichalcogenide (TMD) heterostructures to resolve different exciton degrees of freedom and their nanoscale strain control. |
Thursday, March 18, 2021 9:48AM - 10:00AM Live |
R60.00006: Physical interpretations of multimodal AFM contrast on polymeric materials Greg Haugstad, Melinda Shearer In this work we compare and quantitatively analyze eight AFM measurables that can generate materials contrast on soft matter. These include (i) sliding friction force in contact mode; (ii, iii) adhesion and contact stiffness in force-distance curve mapping (both slow and fast variants, e.g. "force volume" and "peak force" modes), (iv, v) phase imaging in net attractive and net repulsive regime dynamic/AC mode (aka traditional amplitude-modulation "tapping mode"); (vi, vii) contact resonance amplitude and frequency under pulsed-IR excitation (aka resonance-enhanced mode on a Bruker NanoIR3 AFM-IR system); (viii) Fourier-reconstructed conservative and dissipative force versus distance relationships cluster-analyzed (with machine learning) and mapped in intermodulation mode (i.e., using an IntermodulationProducts AB Multi Lockin Analyzer / software system). We apply to a model heterogeneous polymeric film of interest to the paint/coating industry, including phase segregation down to the sub-100 nm spatial scale. Complementarity of information (mechanical, tribological, surface energy, chemical) is of strong interest. |
Thursday, March 18, 2021 10:00AM - 10:12AM Live |
R60.00007: Probing subwavelength in-plane anisotropy with antenna-assisted infrared nano-spectroscopy Ziheng Yao, Xinzhong Chen, Lukas Wehmeier, Yinming Shao, Zimeng Zeng, Fanwei Liu, Alexander S McLeod, Stephanie Gilbert Corder, Makoto Tsuneto, Suheng Xu, Wu Shi, Zihang Wang, Wenjun Zheng, Hans A Bechtel, G Lawrence Carr, Michael Martin, Alex K Zettl, Dmitri Basov, Xi Chen, Lukas Eng, Susanne C Kehr, Mengkun Liu Infrared nano-spectroscopy based on s-SNOM has been employed to probe the vibrational fingerprints at the nanometer scale. However, s-SNOM is less sensitive to the in-plane anisotropy in general. We report a method to probe the in-plane dielectric responses of materials with the help of a metallic disk. As a demonstration, in-plane phonon responses of m-sapphire along b and c axis are identified. The LO phonon frequencies between 350 cm-1 to 800 cm-1 are determined down to a length scale of at least λ/10 without fitting parameters. Our method can be implemented to determine the in-plane anisotropy with high sensitivity, which is difficult for conventional far-field techniques. |
Thursday, March 18, 2021 10:12AM - 10:24AM Live |
R60.00008: Progress in numerical modeling of near-field infrared phenomena at nanometer length scales Patrick McArdle, David Lahneman, Haoyue Jiang, Muhammad M Qazilbash, Tetiana Slusar, Hyun-Tak Kim, Amlan Biswas, Fritz Keilmann, Jingyi Chen The extraction of meaningful nanoscale material properties is reliant on proper modeling of the experimental spectra obtained with broadband, near-field infrared nanospectroscopy. We will discuss our progress towards this goal by presenting combined experimental and numerical modeling results on materials with diverse properties and geometries.. Strong coupling of light to the probe-sample system in highly polar dielectrics such as SrTiO3 leads to multiple phonon-polariton resonances. We show that these resonances should be described by detailed numerical simulations1. We obtain near-field infrared spectra on Cu2S nanoplatelets and show that numerical modeling of the spectra is indispensable for obtaining the properties of nanomaterials. Furthermore, many materials have anisotropic dielectric functions. We have obtained near-field infrared spectra on a uniaxial rutile TiO2 crystal. Proper modeling of spectra from anisotropic materials also requires meticulous numerical simulations. |
Thursday, March 18, 2021 10:24AM - 10:36AM Live |
R60.00009: Cryogen-free Ultra-High Vacuum Low Temperature High Field Proximal Probe System for the Exploration of Low Dimensional Materials Angela Coe, Guohong Li, Eva Andrei Our versatile cryogen-free low temperature scanning probe microscope (SPM) expands SPM capabilities to ultra-high vacuum (UHV), operating at temperatures down to 4K, and magnetic fields up to 9T. We have created an internal vibration isolation unit that connects to cryogen-free cryostats reducing the noise level sufficiently to operate SPMs. Typical cryogen-free systems are too noisy to operate SPMs. The modular design of this SPM accommodates interchangeable probes, including STM, AFM, and MFM. One of the probes is a novel vertical STM design, enabling scanning tunneling topography and spectroscopy in the presence of in-plane magnetic fields up to 9T. This UHV instrument is equipped with stages for sputtering, e-beam film deposition, and exfoliation for in-situ sample preparation and tip conditioning. The SPM is assembled at room temperature in UHV and a novel low-profile vertical transfer mechanism permits transferring the SPM, without breaking vacuum, to a variable temperature, cryogen-free cryostat and magnet. The integration of all these capabilities into one instrument expands in-situ nano-scale characterization of low dimensional systems. |
Thursday, March 18, 2021 10:36AM - 10:48AM Live |
R60.00010: Design of Motorized Coarse Positioning System for Cryogenic Scanning Probe Microscope Kyle Sayre, Sagar Bhandari The ability to investigate quantum properties of electrons in graphene nanostructures allows insights into the behavior of quantum particles and possible applications in future quantum based electronic devices. We designed a low-cost cryogenic Scanning Probe Microscope to image electrons in graphene. One of the challenges in such cryogenic microscopy is the design of coarse positioning system that allows to find the sample at cryogenic temperatures. Our design involves locating the sample through a motorized coarse positioning system mounted to a tabletop cryostat. The components of the microscope are made using a variety of different techniques including 3D printed and CNC milled parts. The designed coarse positioning system operates using separate motors which move the sample in x,y,z directions until the signal is detected by the piezo tube. Two rods with grooves in opposing directions made using CNC milling techniques prevent the platform holding the sample from rotating as it moved to the piezo tube by measuring changes in resistance. This design allows for faster turnaround time for imaging experiments such quantum devices and results in cost savings in terms of cryogenic usage. |
Thursday, March 18, 2021 10:48AM - 11:00AM Live |
R60.00011: Low-cost amplifier design for a cooled Scanning Probe Microscope Donivan Mouck, Sagar Bhandari To further our understanding of 2D materials, it’s crucial to investigate them at the nanoscale. This would shed light on the physics of such materials and helps us develop better electronic and photonic devices. One way to do this is to use a cooled Scanning Probe Microscope (SPM). To image quantum properties of such 2D materials, a SPM tip is raster scanned over the sample while measuring its local electronic properties. In such a system, the feedback mechanism plays an important role in making such measurements. For such feedback systems, low noise/high-gain amplifiers are essential. Unfortunately, such amplifiers are expensive and increase the price of the overall system. We present the design of low-cost amplifier system for such cooled SPM system. Our amplifier design consists of a Wheatstone bridge circuit to detect a voltage change across the SPM cantilever. The signal from Wheatstone bridge is amplified by using a cascade of low-cost operational amplifiers set to high gain and low noise mode. Such system would allow for low budget AFMs making it more accessible by saving a several thousand dollars on commercial amplifiers. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700