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Highlights

Highlights

(top) Bilayer and monolayer MoS2 are interfaced with metal-core phthalocyanine molecules. (bottom) A low-energy absorption peak emerges due to charge transfer across the Pc-MoS2 heterojunction.
(top) Bilayer and monolayer MoS2 are interfaced with metal-core phthalocyanine molecules. (bottom) A low-energy absorption peak emerges due to charge transfer across the Pc-MoS2 heterojunction.
May 3, 2018
Northwestern University

Electronic Coupling in Organic-Transition Metal Dichalcogenide Heterojunctions

Heterojunctions containing two-dimensional materials can give rise to unique effects at the interface or enhance existing optical properties of the composite layers. Using organic molecules in these heterojunctions has the advantage to enable synthetically tunable electronic and optical properties.
Reconfigurable defect structure in MoS2 enables a new circuit element, a “memtransistor,” with high potential for neuromorphic computing.
Reconfigurable defect structure in MoS2 enables a new circuit element, a “memtransistor,” with high potential for neuromorphic computing.
May 3, 2018
Northwestern University

Reconfigurable 2D Materials with Neuromorphic Functionality

Solid-state electronics and advanced computation has spurred significant interest in artificial intelligence and neuromorphic (i.e., brain-like) computing. However, the deterministic correlations between input and action in conventional silicon microelectronics are not well-matched to information processing in biological systems.
Image of silicon metalens mounted on a transparent, stretchy polymer film, without any electrodes. The colorful interior is produced by the large number of nanostructures courtesy of the Capasson Laboratory. Alan She, Shuyan Zhang, Samuel Shian, David R. Clarke, and Federico Capasso, “Adaptive metalenses with simultaneous electrical control of focal length, astigmatism, and shift,” Sci. Adv. 4, eaap9957 (2018) [DOI: 10.1126/sciadv.aap9957]
Image of silicon metalens mounted on a transparent, stretchy polymer film, without any electrodes. The colorful interior is produced by the large number of nanostructures courtesy of the Capasson Laboratory. Alan She, Shuyan Zhang, Samuel Shian, David R. Clarke, and Federico Capasso, “Adaptive metalenses with simultaneous electrical control of focal length, astigmatism, and shift,” Sci. Adv. 4, eaap9957 (2018) [DOI: 10.1126/sciadv.aap9957]
May 1, 2018
Harvard University

Forward-looking Metalens

David R. Clarke (Materials Science)
Inspired by the human eye, a team led by Clarke at the Harvard MRSEC has reported in Science Advances an adaptive metalens that is a flat, electronically-controlled artificial eye. This new lens which combines breakthroughs in artificial muscle and lens technologies simultaneously controls focus, astigmatism, and image shift.
Crushing Soda Cans: Predicting the Stability Landscape of Shell Buckling
Crushing Soda Cans: Predicting the Stability Landscape of Shell Buckling
May 1, 2018
Harvard University

Crushing Soda Cans: Predicting the Stability Landscape of Shell Buckling

Michael P. Brenner (AppMath), John W. Hutchinson (MechEng),  and Shmuel M. Rubinstein (AppPhy)
Crushing a soda can from top to bottom is easier if it is dented initially on the side. Predicting the force needed to crush a dented can, however, which is of critical importance for structural reliance of materials engineering is quite challenging.
Figure 1. Visualizations of the charge density of the two electrons trapped in an oxygen vacancy at zero field in (a) MgO, (b) CaO, (c) SrO, and (d) BaO. Similar visualizations at a field of 22 MV/cm in the +x direction are shown for (e) MgO, (f), CaO, (g) SrO, and (h) BaO. Red, blue, cyan, green, and grey spheres represent O, Mg, Ca, Sr, and Ba ions, respectively.
Figure 1. Visualizations of the charge density of the two electrons trapped in an oxygen vacancy at zero field in (a) MgO, (b) CaO, (c) SrO, and (d) BaO. Similar visualizations at a field of 22 MV/cm in the +x direction are shown for (e) MgO, (f), CaO, (g) SrO, and (h) BaO. Red, blue, cyan, green, and grey spheres represent O, Mg, Ca, Sr, and Ba ions, respectively.
Apr 27, 2018
Massachusetts Institute of Technology

Strong Electric Fields Tune the Stability of Ionic Defects in Oxides

Bilge Yildiz and Krystyn Van Vliet
Intellectual Merit: No ceramic crystal is perfect, and structural imperfections including point defects are responsible for many technologically desirable properties of ceramics. Applications such as modern computer memories rely on controlling defects inside a crystal by exposing them to large electric fields. High field effects on defective crystals, however, remain challenging to control and address.
Figure 1: The stiffness of mucus can be modified by targeting different associative groups on the mucin molecules. By performing both micro- and macro-rheological measurements on these gels, additional insight into the structural rearrangements leading to the observed differences in the bulk mechanical properties (such as heterogeneity) can be inferred.
Figure 1: The stiffness of mucus can be modified by targeting different associative groups on the mucin molecules. By performing both micro- and macro-rheological measurements on these gels, additional insight into the structural rearrangements leading to the observed differences in the bulk mechanical properties (such as heterogeneity) can be inferred.
Apr 27, 2018
Massachusetts Institute of Technology

How Mucus Keeps You Healthy

Katharina Ribbeck and  Garreth McKinley
Intellectual Merit:
Scanning Electron Microscope Image of a High-Temperature NanoThermoMechanical Diode.
Scanning Electron Microscope Image of a High-Temperature NanoThermoMechanical Diode.
Apr 25, 2018
University of Nebraska - Lincoln

NanoThermoMechanical Thermal Computing

Sidy Ndao (University of Nebraska-Lincoln)
Limited performance and reliability of electronic devices at extreme temperatures, intensive radiation found in space exploration missions and earth-based applications requires the development of alternative computing technologies. Nebraska MRSEC researchers have designed and prototyped the world’s first high-temperature thermal diode. They have demonstrated the use of near-field thermal radiation from smooth and metamaterial surfaces to achieve thermal rectification at high temperatures. They named the technology NanoThermoMechanical thermal computing.
Nebraska MRSEC undergraduates Spencer Prockish (left) and Peter Kosch help elementary students design their own experiments to determine how a magnet’s size and shape affect its strength.
Nebraska MRSEC undergraduates Spencer Prockish (left) and Peter Kosch help elementary students design their own experiments to determine how a magnet’s size and shape affect its strength.
Apr 25, 2018
University of Nebraska - Lincoln

Nebraska MRSEC Puts a “Spark” in Summer Learning

Rebecca Lai, Jocelyn Bosley, and Krista Adams (University of Nebraska-Lincoln)
In Summer 2017, Nebraska MRSEC partnered with the Foundation for Lincoln Public Schools to offer a new, STEAM-based summer learning program. Spark Summer Learning provides opportunities for students in grades K-5 to explore science, technology, engineering, art, and math in an immersive setting, engaging students in problem-based learning through hands-on “maker” projects.
Optically-induced polarization reversal in hybrid MoS2/BaTiO3 (BTO) structures: geometry of experiment (left panel) and polarization state of BaTiO3 (right panels). The BaTiO3 surface is partially covered with MoS2. Under ultraviolet (UV) illumination polarization of the BaTiO3 film underneath the MoS2 flake is reversed as indicated by color.
Optically-induced polarization reversal in hybrid MoS2/BaTiO3 (BTO) structures: geometry of experiment (left panel) and polarization state of BaTiO3 (right panels). The BaTiO3 surface is partially covered with MoS2. Under ultraviolet (UV) illumination polarization of the BaTiO3 film underneath the MoS2 flake is reversed as indicated by color.
Apr 25, 2018
University of Nebraska - Lincoln

Optical Control of Polarization in Hybrid 2D-Ferroelectric Structures

Alexei Gruverman and Alexander Sinitskii (University of Nebraska-Lincoln) and Chang-Beom Eom (University of Wisconsin-Madison)
Switchable electric polarization of ferroelectric materials can serve as a state variable in advanced electronic systems, such as non-volatile memories and logic. Control of ferroelectric polarization by external stimuli is the key component for these systems. Nebraska MRSEC researchers have discovered an optical control of the hybrid structures comprising a two-dimensional (2D) semiconducting material, molybdenum disulfide (MoS2), and ultrathin ferroelectric barium titanate (BaTiO3).
Magnetic structure of hexagonal ytterbium ferrite (h-YbFeO3) in which iron (Fe) magnetic moments (indicated by blue arrows) are anti-aligned to ytterbium (Yb) magnetic moments (indicated by grey arrows), thus revealing ferrimagnetism of multiferroic hexagonal ferrite h-YbFeO3.
Magnetic structure of hexagonal ytterbium ferrite (h-YbFeO3) in which iron (Fe) magnetic moments (indicated by blue arrows) are anti-aligned to ytterbium (Yb) magnetic moments (indicated by grey arrows), thus revealing ferrimagnetism of multiferroic hexagonal ferrite h-YbFeO3.
Apr 25, 2018
University of Nebraska - Lincoln

Direct Observation of Ferrimagnetism in a Multiferroic Hexagonal Ferrite

Xiaoshan Xu, Peter Dowben, and Evgeny Tsymbal (University of Nebraska-Lincoln)
Multiferroics is a class of materials that exhibits a coexistence of electric and magnetic polarizations.  Coupling of these polarizations is potentially useful for energy-efficient information storage and processing. Hexagonal rare-earth ferrites (h-RFeO3, where R is rare-earth element and Fe is iron) are new family of multiferroic materials. Magnetic interactions between rare-earth and iron ions in h-RFeO3, may amplify the weak ferromagnetic moment of iron, making these materials more appealing as multiferroics.

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