News
Seeking post-doctoral candidate in superconducting nanowires
Post-doctoral candidate sought with experience suitable for performing research in one or more of the following areas: superconducting electronics/detectors, low temperature physics, applications of superconducting devices, and related research topics. The post-doc will have an opportunity to develop superconducting-nanowire-based devices and apply them to quantum information science, energy-efficient classical computation, and the study of superconducting physics, as well as the opportunity to collaborate on other ongoing and new projects in our research group. The new hire will assist in planning and management of group activities, especially in mentoring graduate and undergraduate students, planning and executing research programs, and raising funds for research. The candidate must have a Ph.D. in Electrical Engineering, Applied Physics, or a related field. The initial emphasis of the work will be on the development superconducting circuits based on nanowire cryotrons for applications to superconducting memories and optical-electronic interfaces. Applications to single-photon will also be investigated.
Interested candidates may apply at http://goo.gl/forms/mleVXYlfWydeymej2. If this link is unavailable to you for any reason (some geographic locations block google forms), you may contact Dorothy Fleischer (dotf@mit.edu) for assistance in completing the form. Applications will be evaluated as received, with a candidate selection and appointment expected in the Fall of 2016.
Andrew Dane awarded MRS symposium student presentation prize at MRS Spring 2016
Congratulations to QNN member Andrew Dane for being awarded the MRS symposium student presentation prize for his talk “Bias Sputtered Few-Nanometer-Thick Niobium Nitride for Superconducting Devices” at the Spring 2016 Materials Research Society meeting in Phoenix. He presented in the symposium “Tailoring Superconductors—Materials and Devices from Basic Science to Applications.”
Emily Toomey awarded NSF fellowship
Congratulations to Emily Toomey on receiving the National Science Foundation Graduate Research Fellowship. This prestigious and competitive award will support her work for three years.
New Paper: “Designs for a quantum electron microscope”
One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This ‘quantum weirdness’ could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or “quantum electron microscope”. A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope.
“Designs for a quantum electron microscope.” P. Kruit, R.G. Hobbs, C-S. Kim, Y. Yang, V.R. Manfrinato, J. Hammer, S. Thomas, P. Weber, B. Klopfer, C. Kohstall, T. Juffmann, M.A. Kasevich, P. Hommelhoff, K.K. Berggren. Ultramicroscopy, Available online 10 March 2016, ISSN 0304-3991, http://dx.doi.org/10.1016/j.ultramic.2016.03.004.
New Papers: “Multilayer block copolymer meshes by orthogonal self-assembly” and “The orientations of large aspect-ratio coiled-coil proteins attached to gold nanostructures”
“Multilayer block copolymer meshes by orthogonal self-assembly”, Amir Tavakkoli K. G., Samuel M. Nicaise, Karim R. Gadelrab, Alfredo Alexander-Katz, Caroline A. Ross & Karl K. Berggren. Nature Communications, (2016)
DOI: 10.1038/ncomms10518
Continued scaling-down of lithographic-pattern feature sizes has brought templated self-assembly of block copolymers (BCPs) into the forefront of nanofabrication research. Technologies now exist that facilitate significant control over otherwise unorganized assembly of BCP microdomains to form both long-range and locally complex monolayer patterns. In contrast, the extension of this control into multilayers or 3D structures of BCP microdomains remains limited, despite the possible technological applications in next-generation devices. Here, we develop and analyse an orthogonal self-assembly method in which multiple layers of distinct-molecular-weight BCPs naturally produce nanomesh structures of cylindrical microdomains without requiring layer-by-layer alignment or high-resolution lithographic templating. The mechanisms for orthogonal self-assembly are investigated with both experiment and simulation, and we determine that the control over height and chemical preference of templates are critical process parameters. The method is employed to produce nanomeshes with the shapes of circles and Y-intersections, and is extended to produce three layers of orthogonally oriented cylinders.
Learn more about the researchers and their motivations behind this work in these articles from MIT news and Science News.
“The Orientations of Large Aspect-Ratio Coiled-Coil Proteins Attached to Gold Nanostructures“, Jae-Byum Chang, Yong Ho Kim, Evan Thompson, Young Hyun No, Nam Hyeong Kim, Jose Arrieta, Vitor R. Manfrinato, Amy E. Keating & Karl K. Berggren. Small (2016)
DOI: 10.1002/smll.201502419
Methods for patterning biomolecules on a substrate at the single molecule level have been studied as a route to sensors with single-molecular sensitivity or as a way to probe biological phenomena at the single-molecule level. However, the arrangement and orientation of single biomolecules on substrates has been less investigated. Here, the arrangement and orientation of two rod-like coiled-coil proteins, cortexillin and tropomyosin, around patterned gold nanostructures is examined. The high aspect ratio of the coiled coils makes it possible to study their orientations and to pursue a strategy of protein orientation via two-point attachment. The proteins are anchored to the surfaces using thiol groups, and the number of cysteine residues in tropomyosin is varied to test how this variation affects the structure and arrangement of the surface-attached proteins. Molecular dynamics studies are used to interpret the observed positional distributions. Based on initial studies of protein attachment to gold post structures, two 31-nm-long tropomyosin molecules are aligned between the two sidewalls of a trench with a width of 68 nm. Because the approach presented in this study uses one of twenty natural amino acids, this method provides a convenient way to pattern biomolecules on substrates using standard chemistry.