Sambandamurthy Ganapathy - US grants

Technical Abstract:
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This Faculty Early Career Award funds a proposal that seeks to make significant impact on our current understanding of the physics of quantum phase transitions (QPT) in superconducting nanostructures. Nanometer scale indium oxide devices with precisely engineered structural and transport characteristics will be utilized to probe the subtle interplay between disorder and interaction across the superconductor-insulator QPT. These experiments will provide explicit information about the microscopic conduction mechanisms when the transition is tuned via disorder, density or magnetic field in one and two-dimensional devices. The results will improve our current understanding of the phase coherence and emergence of novel collective phases near quantum critical points. Research is closely integrated with the education component of the proposal: an undergraduate laboratory experiment to explore quantum nature of electrons will be developed and hands-on research opportunities will be provided to a broader group including high school science teachers in the Buffalo region. The education plan also seeks to improve the learning experience of students in undergraduate introductory physics courses through a variety of modern teaching methods.

Non-technical Abstract:
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The goal of this Faculty Early Career Award is to effectively combine experimental research to explore quantum phases near critical points in superconducting nanostructures with education and outreach programs to train a new generation of undergraduate and graduate students and high school teachers. The research proposal will seek an unprecedented control in engineering the microstructure and property of the material used (indium oxide) and the transport measurements in nanodevices proposed herein are expected to transform our current understanding of quantum phases in one and two-dimensional systems. The integrated educational aspects will involve several projects closely related to the research activities in the PI?s group. A new undergraduate laboratory experiment for learning the basic concept of quantum nature of electrons will be developed with the help of undergraduate students at the university or K-12 physics teachers in the Buffalo region. Modern teaching methods will be implemented in introductory physics courses for non-majors, thereby improving the learning experience and scientific awareness among a wider student body. The results of the research and educational activities will be disseminated to the general public through participation in local art festivals and New York State?s STEP program.

****NON-TECHNICAL ABSTRACT****
Graphene, which consists of a single atomic layer of carbon atoms, has produced dramatic new physical phenomena and has potential for exciting technological applications, such as high speed transistors that could revolutionize electronics. This project will explore graphene in new ways by using polarized infrared light, with wavelengths up to several thousand times longer than visible light. The changes in the polarization of the light after interacting with graphene will help to resolve questions that have been left unanswered by other techniques as well as test new theoretical predictions. An example includes why/how graphene absorbs light at wavelengths that one would not expect. Furthermore, this project will test a theoretical predication that the polarization of transmitted light makes unusual jumps as a magnetic field is smoothly increased. In addition to providing new insights into this unusual and fundamentally important system and training PhD students, the project will reach out to under-represented groups in science by starting a radio-controlled flying club (~20 students) in a Buffalo public high school. The club will meet twice a month and each meeting will begin with hands-on lessons on how basic physics and advanced technology combine to make radio-controlled flight possible.

****TECHNICAL ABSTRACT****
Graphene, which consists of a single atomic layer of carbon atoms, has produced dramatic new physical phenomena, such as massles Dirac quasiparticles, and has potential for exciting technological applications, such as high speed room temperature ballistic transistors and tunable infrared detectors/sources. This project will explore graphene in new ways by using polarized infrared light (5-1200 meV) in magnetic fields up to 10T to probe the Hall effect of this chiral material. The changes in the polarization of the reflected and transmitted light will help to resolve questions that have been left unanswered by other techniques (absorption of radiation below the expected absorption edge, the asymmetry of electron and hole states in bilayer graphene, and the unusual temperature and magnetic field dependence of the dc Hall angle) as well as test new theoretical predictions (circular dichroism in the absence of a magnetic field in bilayer graphene and plateaus in the THz Hall response of graphene). In addition to providing new insights into this unusual and fundamentally important system and training PhD students, the project will reach out to under-represented groups in science by starting a radio-controlled flying club (~20 students) in a Buffalo public high school. The club will meet twice a month and each meeting will begin with hands-on lessons on how basic physics and advanced technology combine to make radio-controlled flight possible.

This cryogen-free system with its superconducting magnet and wide sample temperature range capabilities for magneto optical and magneto transport measurements in a wide range of frequency builds on faculty expertise at the University at Buffalo SUNY (UB), strongly supports existing research programs and will serve as a user facility for the current members of UB community and proposed new faculty hires in the general area of Material Science and Engineering. The system will allow UB researchers to expand their research activities into a broad range of new applications, such as new electronic, photonic, spintronic, and energy devices, and thus, enhance existing grants while positioning them well for investigation of novel materials. This system will allow interdisciplinary research training for the undergraduate and graduate students and postdocs. The proposed system will be accessible to researchers in the fields of nanoelectronics, semiconductor physics and energy related research from the community colleges and start-up companies in the Buffalo area. This training is valuable for the students in the western New York region for their future careers in high tech industry, academia and in national laboratories.

This Major Research Instrumentation award supports and enhances the interdisciplinary research activities of several research groups at the University at Buffalo, SUNY (UB) through the acquisition of a cryogen-free magnet cryostat system with optical and electrical measurement capabilities. The research activities range from transport measurements on nanoscale oxide materials near phase transitions, mesoscopic phenomena in semiconductors and two-dimensional (2D) materials, growth and characterization of 2D transition metal dichalcogenides (TMD), the interplay of disorder and topologically-protected transport in 2D materials, magneto reflectance and polarization measurements on TMDs, Hall effect in superconductors, THz emission from 2D materials and heterostructures, and next generation power devices. With a potential to perform concurrent optical (from UV to mid-IR frequency range) and transport (both AC and DC) measurements, the system will serve a wide user base with varied technical needs. This cryogen-free magnet system will enable all UB researchers, including underrepresented minorities and women within our diverse academic community, to access its state-of-the-art capabilities.

This major research instrumentation project is to acquire a high-performance Electron Beam Lithography system for research, education and broader impact in the Western New York region. The system uses an ultra-narrow beam of high energy electrons (1.8 nm wide) to define features on the scale of tens of nanometers. The unique capabilities of this advanced nanofabrication tool will enable crucial research in a broad range of fields spanning engineering, physics, chemistry, materials science and biology. The state-of-the-art tool will be installed at the University at Buffalo and provide both onsite and remote access to a large number of students, faculty, researchers and entrepreneurs across the region. The unique feature of the tool is the ability to define sub-10 nm dimension structures with fast writing speed over large areas. This feature is very important for cutting edge research in electronics and photonics. The aim is to rapidly translate the fundamental knowledge gained in academic laboratories to real world applications. Another feature of the tool is the ability to define nm structures on flexible substrates that are essential for biomedical applications. Undergraduate and graduate students in the engineering and science disciplines will have access to the tool. They will be trained in its use through courses and programs offered by the electrical engineering department at the University at Buffalo. The tool will enable cutting-edge research across computing, communications, healthcare, and education. The research opportunity given to undergraduate and graduate students will help build the skills of the future workforce for knowledge-based economy and maintain the economic competitiveness of the US. The tool will improve the research infrastructure in the western New York region and positively impact the economy of the region. The remote access feature will enable students to submit their designs for fabrication from any location. The instrument will also contribute to strong outreach programs in engineering and applied sciences. Investigators will provide mentorship to underrepresented students in science and engineering.

Electron beam lithography is an indispensable tool for advanced research in electronics, photonics, physics, and materials science. The tool will enable research in a broad range of topics: low power non-volatile high speed ferroelectric and magneto-electric based logic and memory devices for energy efficient data intensive computing applications; emerging low power and efficient quantum devices; nano-electronics based on two-dimensional (2D) materials; high power flexible electronics based on widebandgap semiconductors; room temperature THz devices based on coupling of optical phonons in III-V semiconductors to graphene plasmonic structures; understanding of the fundamental physics in correlated electron systems; THz plasmonic structures for chemical and biological sensing; graphene plasmonic array for THz communication; and characterization of 2D materials, heterointerfaces, and devices. These high impact research have applications that range from computing, communication, energy and health. It will also help in understanding fundamental physics in correlated materials and the switching dynamics in technologically important antiferromagnetic oxides. The proposed tool to be acquired will have large acceleration voltage, sub-10nm lithographic resolution, high beam position resolution, sub-20 nm stitching and overlay accuracy, tunable field size up to 3000 micrometers for high throughput writing, and height correction feature for writing on flexible substrates. These unique features are essential to carry out the proposed research.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Probe station is an essential scientific instrument used by scientists and engineers to test and measure new materials and devices. This major research instrumentation project will acquire a high-performance closed cycle liquid cryogen free low temperature probe station with electrical, magnetic, optical and high frequency probing capabilities for high impact research and STEM education at the University at Buffalo (UB). The state-of-the-art tool with several unique technical features will immensely improve the research infrastructure at UB. The tool will have broad impact with usage from faculties, researchers, students, and entrepreneurs at UB and other institutes in the western New York region (WNY). The unique feature of the tool is the ability to simultaneously probe magneto-optical-electrical properties across a wide range of temperatures (5 K to 500K). The salient technical features of the tool will enable high impact research in a broad range of fields spanning engineering, physics, chemistry, materials science, and biology. The unique features of the tool are the ability to probe materials and devices with magneto-electrical, magneto-RF, electro-optical, magneto-RF-optical signals and combinations thereof. These features are necessary for innovative research in materials and devices for quantum information science, 5G and beyond communications and next generation energy technologies. Furthermore, the tool will enable probing the fundamental science and chemistry of emergent materials and interfaces opening the avenues for new knowledge. Undergraduate and graduate students in the engineering and science discipline at UB and across WNY region will have access and training to the tool through courses and programs offered by various engineering and science departments at UB. The tool will have positive effect across a wide range of topics of current national focus on maintaining US leadership. These include semiconductors, quantum information science, 5G and beyond communication, clean energy technologies. The research opportunity given to undergraduate and graduate students will help build the skills of the future workforce and maintain the economic competitiveness of the US. The tool will be incorporated into and managed by the shared instrumentation and equipment portal at UB providing easy access to both academic and industrial users. The strong outreach programs underway at UB will also use this facility. <br/><br/>Probe stations are essential tools for engineers and scientists to investigate fundamental science through convenient, fast, repeatable measurements of electrical, optical, and magnetic properties of materials and devices producing consistent results. They are versatile, flexible but more importantly easy, fast to use research platforms that can be used by multiple researchers in electronics, photonics, engineering, materials science, physics, and chemistry departments. The unique features of the tool are the ability to probe materials and devices with magneto-electrical, magneto-RF, electro-optical, magneto-RF-optical signals and combinations thereof. The tool will enable research in a broad range of topics: low power non-volatile high speed magneto-electric based logic and memory devices for energy efficient data intensive computing applications; next generation RF and power devices using ultawidebandgap semiconductors; tunnel FETs and cold electron transistors based on emerging 2-D materials; high power flexible electronics based on widebandgap semiconductors; room temperature mid-infrared (MIR)/THz devices based on coupling of optical phonons in III-V semiconductors to graphene plasmonic structures; understanding of the fundamental physics in correlated electron systems using noise spectroscopy; high temperature superconductors for quantum information science and characterization of 2-D materials, heterointerfaces, and devices. These high impact research have applications that range from computing, communication, and energy. It will also help in understanding fundamental physics in the 2-D magnets and polar molecules. The proposed tool to be acquired will have high vertical magnetic fields, with DC, optical and RF probing capabilities. These unique features are essential to conduct the proposed research.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.