# REU Research Projects

Projects include experimental, computational, and theoretical work in a variety of areas within or related to materials physics. Completion of a first-year physics or chemistry course sequence is a prerequisite for all projects. Additional prerequisites are noted in the project descriptions.

**Nanoscale devices** (Prof. Paola Barbara) Prof. Barbara’s research group studies the transport properties of devices made with atomically thin materials. Current research projects mainly involve molybdenum disulfide, graphene, and other two-dimensional materials, which are of interest both for their basic properties (such as superconductivity) and for applications (such as chemical sensors, detectors of THz radiation, photovoltaic cells and sources of electromagnetic radiation). Students learn how to grow these materials via chemical vapor deposition and characterize their optical properties via Raman spectroscopy. They will also fabricate devices and learn how to test their electrical transport properties. Specific projects will be defined later in the spring and designed to complement ongoing research.

**Structure of soft matter** (Prof. Daniel Blair) The Blair group investigates the structure and function of soft and biological matter using a variety of tools and approaches. Systems of interest include colloidal glasses and gels, unsteady microfluidic flows in non-Newtonian fluids, non-linear rheology of biological polymers, and diffusion in model networks. The primary tools for this work are three-dimensional laser scanning confocal microscopy, advanced image processing, bulk rheology, opto- and micro- rheology, and laser light scattering. Students in the lab use high-resolution microscopy techniques to acquire time-resolved three-dimensional image data which is then processed using advanced image processing software developed for MATLAB and IDL. A summer REU student will contribute to ongoing efforts to measure the microscopic profile of deformed bio-polymer matrices. The goal is to understand the microscopic origins of the non-linear rheology of these materials. By directly imaging a fluorescently labeled network of polymers during a macroscopically applied shear strain, the student will measure how the network deforms locally. This will reveal the length scale that the local shear becomes non-affine, a critical feature of current theories developed to understand biological polymers.

**Soft matter in construction: models and simulations of soft solids** (Prof. Emanuela Del Gado) The Del Gado group uses statistical mechanics and computational physics to investigate the structure, dynamics, and emerging mechanics in soft solids. The materials of interest range from colloidal gels to jammed dense suspensions and tissues, to self-assembled nanocomposite interfaces, to the sticky gels formed during cement hydration and responsible for cement strength. The focus is on unraveling how nano-scale structure and effective interactions may interplay with deformation or other non-equilibrium conditions to change the material properties. The aim is to devise new paradigms for material design, to obtain specific unusual rheological behavior or more sustainable formulations of smart compounds. Motivated by the need to reduce greenhouse gas emissions associated with cement production, the work on cement gels aims at a first-principles understanding of cement properties, a prerequisite to controlling the processing and formulating alternatives. The student will perform computer simulations of model gels or other soft solids, and use novel analytical tools to investigate their microscopic spatial and temporal complexity. Project ideas this year will include materials for construction in space, double network gels, and fracture of soft solids. Preference will be given to students with computational skills.

**Physics education research** (Leanne Doughty): The Doughty group seeks to understand and improve student experiences in undergraduate physics courses. Student success and persistence in a major is closely tied to their sense of belonging and self-efficacy within the discipline. As such, one area of interest is the development of students’ physics identity earlier in the major. Course-based Undergraduate Research Experiences (CUREs) affords students opportunities to engage in authentic research during their lower-division courses. CUREs provide students access to real data and practice with analytic tools, such as computational modeling and statistical analysis. An REU student could develop a materials physics CURE for our sophomore-level Modern Experimental Physics course. The student would collaborate with other REU students and members of other research groups in the department to identify an appropriate research question and collect the required data. The student would also develop instruction to scaffold student engagement with the relevant physics concepts and the computation involved in the analysis.

**Simulations of spatiotemporal dynamics ** (Prof. David Egolf) The Egolf group employs large-scale computation and theory to study a variety of systems driven far from equilibrium. Typically, the systems investigated exhibit complicated spatiotemporal dynamics, and, in particular, spatiotemporal chaos. The group has recently studied the behavior of fluid systems, granular systems, cardiac tissue, and neural tissue, as well as simpler model systems. Students in this group will learn a wide variety of scientific techniques from statistical physics, nonlinear dynamics, mathematical modeling, and parallel computing. Preference will be given to students who can program in C or C++.

**Quantum computation with ion traps ** (Prof. Jim Freericks) The Freericks group is funded for quantum information research by the National Science Foundation and the Department of Energy. The focus is to find ways to do interesting science now, with the currently available quantum hardware. We work on a wide range of problems in physics and chemistry in this research program. Recent projects include developing a new quantum computing algorithm to simulate fermionic Green’s functions and determining how to simulate driven dissipative quantum systems. Completion of at least one course in quantum mechanics is a requirement for this project. Preference will be given to students who also know at least one high-level programming language suitable for numerical work like FORTRAN, C, C++, Python, or Matlab (Matlab or python preferred). A previous REU student on this project was named a finalist in the 2012 LeRoy Apker Award of the American Physical Society, awarded to the top undergraduate researchers in all fields of physics in the US. That student was a co-author of a *Nature* paper, a *Physical Review Letter* paper, and a *Physical Review A* article. Since 2013, twelve students worked on this project, with ten publications completed in a variety of different journals.

**Computational studies of 2D materials ** (Prof. Amy Liu) This research group uses computational methods to understand and predict structural, electronic, and vibrational properties of materials, including superconductors, clusters, and nanostructures. One area of interest is in the properties of layered materials that can be exfoliated into atomically thin samples, similar to graphene. The electronic and optical properties of molybdenum disulfide, for example, have been shown to change dramatically as the number of layers is reduced. In the 2D limit, these materials tend to be very sensitive to the environment and the choice of substrate. An REU student might perform simulations to determine how structural and electronic properties of the 2D material varies with the substrate or the type of defects present. The goal is to understand the physics behind these effects and understand how to optimize these materials for nanoscale devices. Preference will be given to students who have completed a sophomore-level modern physics course.

**3D Nanowire Networks and Foams** (Prof. Kai Liu) Prof. Kai Liu’s research focuses on the synthesis and experimental investigation of nanostructured materials, particularly in nanomagnetism and spintronics, which have potentially important technological applications in magnetic recording, low dissipation information storage, and nanoelectronics. The group is currently exploring interconnected nanowire networks and nanoporous metallic nanowire foams that are extremely lightweight, with enormous surface areas while maintaining mechanical stability. Such nanostructures are being studied for 3D information storage, neuromorphic computing, as well as particulate filtration, etc. Student(s) working on the project will be involved with all aspects of the research, including sample synthesis, characterization, data analysis, manuscript preparation, and research presentation.

**Theory and simulation of soft matter** (Prof. Peter Olmsted) Professor Olmsted studies a wide range of systems, including liquid crystals, surfactant solutions, membranes, polymer gels and networks, polymer melts and blends. He has strong interest in biological problems and materials, including proteins, membranes, and cell biophysics (the figure shows a predicted free energy landscape for lipid bilayers). General themes are (1) the role of complex microstructure and fluctuations on equilibrium phase behavior and kinetics, and (2) strongly non-equilibrium effects, such as the effect of shear flow on the rich degrees of freedom in complex fluids. Theoretical tools for Professor Olmsted’s research include statistical mechanics, hydrodynamics, and computer modeling. Students with programming skills will be able to write programs to perform calculations of increasing complexity; alternatively, Mathematica or MatLab, or more sophisticated molecular dynamics packages may be used for some problems. Some projects will be appropriate for students with very strong mathematical skills in linear algebra, differential equations, and vector calculus/differential geometry. Project ideas this year include simulations and calculations of polymer glasses, the physics that underlies the process of protein production (“from the nucleus to the ribosome and back”), the non-Newtonian fluid mechanics of Additive Manufacturing (3D printing), and analysis of computer simulations of small molecules diffusing in the skin. It is likely that other projects will emerge between now and then!

**Nano and micro technology ** (Prof. Mak Paranjape) The Paranjape group works on the design, fabrication, and characterization of biochemical and biomedical sensors, microfluidic devices, and polymers for drug delivery and tissue scaffolding applications. Students are trained in general laboratory safety and cleanroom etiquette, followed by training on state-of-the-art processing equipment such as mask aligners for photolithography, reactive ion etcher for dry plasma surface treatments, magnetron sputterer, and electron beam evaporators for metal deposition, furnaces for carbon nanotube and oxide growth, and scanning electron microscopy for image capture and nanolithography direct-write applications. Examples of some of the past summer projects include: i) silk and polymer electrodeposited nanoparticles for drug delivery, ii) biodegradable polymer nanofibers for tissue scaffolding, iii) conducting sub-micron polymer nanofibers for mimicking nerve myelination, iv) a nanofiber piezoelectric energy harvesting device, v) nebulized polymer nanoparticles for drug delivery, and vi) investigating 2D materials (MoS2 and MoTe2) in FET transistor configurations for sensing applications.

**Synthesis and characterization of multicomponent nanoparticles **(Prof. Ed Van Keuren (new window)) The main research in the Van Keuren group is the study of organic nanoparticles and involves both investigations of their formation in solution and their use in novel applications. We use a variety of optical methods to characterize the nucleation and growth of the particles. Several current projects in the lab are: the development of liquid-core polymer shell nanocapsules, nanoparticles contrast agents for MR and ultrasound imaging and charge transfer nanocrystals for organic electronics. The project would be well suited to a student with an interest and background in optics and/or chemistry and does not require advanced coursework in physics.

** Topological and magnetic phase transitions in 3D magnetic systems **(

**Prof. Gen Yin**).

**The Yin group investigates the ground-state textures, topological transitions, and magnetic phase transitions in 3D magnetic materials, networks, and interfaces. REU students involved in this project will use micromagnetic simulations to understand and explore magnetic orders in complex 3D structures or interfaces. The goal is to associate real-space-resolved phenomenological magnetic parameters with magnetometry, transport, and imaging measurements. The project will produce simulation data using GPU-accelerated micromagnetic packages to produce minor-loop hysteresis curves and 3D spin-texture images at finite temperatures. Such simulation results will be machine-learned to correlate experimental observables with parameters in micromagnetic simulations. REU students in this project will write scripts to perform simulations and carry out artificial intelligence studies using multi-layer neural networks. Students who are familiar with C++, Python, and GPU computing are best suited for this project.**

**Dynamics of soft matter **(Prof. Jeff Urbach)** **The Urbach group investigates complex dynamical systems, employing tools from statistical physics and nonlinear dynamics, together with advanced imaging techniques, image processing, and computer simulations, to develop quantitative, testable descriptions of multifaceted, interacting, ever-changing systems that might at first glance seem like a complicated mess. Current projects include shear thickening in dense suspensions and the phase behavior of colloidal rod suspensions that form liquid crystals and glasses. Students in the group typically learn to use high-resolution microscopy, analysis software, and a variety of sample preparation and measurement techniques to quantify the structure and dynamics of fluids under flow and deforming soft solids.