Basic research and technology:

Some of the most interesting physical phenomena include superconductivity, a phenomenon wherein a material has zero electrical resistance and expels small magnetic fields when cooled below a material specific critical temperature, and heavy fermion behavior, in which electrons behave as if they were much more massive than typical electrons by factors of several hundred. Many of the materials that have been responsible for recent advances in physics and technology are rare earth and actinide compounds consisting of three or more elements in which the localized (attached to a specific ion) d-and f-electrons are admixed with conduction electrons (free to move within the metal).  A major goal of our project were to study selected unconventional superconductors, such as iron-based pnictites and chalcogenites and heavy fermions, in order to contribute to a more global understanding of the novel phenomenon of superconductivity that takes place at high temperatures. Specifically, we studied two major themes in condensed matter physics: quantum critical phenomena and unconventional superconductivity. A quantum phase transition takes place at zero temperature and describes a phase transition between competing ground states driven by an external parameter such as chemical composition, pressure, or magnetic field. The recent studies of unconventional superconductors show that superconductivity develops in proximity to a magnetically ordered phase. This raises the possibility of quantum phase transitions in these systems arising from competing types of such orders. We measured physical properties of f-electron materials as functions of temperature, magnetic field, applied pressure, and chemical substitution, yielding important clues that shed light on the underlying mechanism of superconductivity. While other present studies of iron-based superconductors mainly focus on the understanding of the normal state properties of these superconductors and on the mechanism of superconductivity, our studies enhance our fundamental understanding of the extent to which a quantum phase transition controls the finite temperature properties of these superconductors and promise insight into the mutual interplay between superconductivity and magnetism. These studies could also offer clues about other unconventional superconductors, such as the cuprates, and contribute to a more global understanding of the novel phenomenon of high temperature superconductivity. Unveiling what these various materials share in common and what aspects of their behavior are system specific lead to basic scientific insights with important practical relevance to developing functional materials for technological applications.  Our studies of the physics of strongly correlated electron systems impact science and engineering research in many beneficial ways.  

Education, training, and professional development:

These projects provided opportunities for research, teaching, and mentoring, for graduate and undergraduate students.  Since these projects were not overly large and unwieldy, the researchers pursuing them necessarily became trained in a wide array of skills and technologies.  Specifically, these projects have contributed to the development of experimental skills and experience with low-temperature systems, electronics and mechanical design and construction, equipment “debugging”, planning and executing microcomputer interfaces for automated experimental control and data acquisition, and programming including writing special-purpose programs in high-level languages.  Also, these projects has exposed the students to new physics phenomena that are at the forefront of condensed matter physics.  Finally, thedy provided a unique opportunity for developing scientific presentation and writing skills.  All students participated in regular laboratory group as well as departmental meetings.  In addition, they also attended national and international conferences where they presented their work.  Moreover, they contributed to manuscript preparation and writing.

The principal investigator believes that professional development is a fundamental component of the training experience of graduate students.  For this reason, she has invested a lot of time, effort, and dedication towards this goal, and she has strived to provide a stimulating, positive, and constructive experience for all group members.  Specifically, the principal investigator and each group member initially identified his/her career goals and assessed the developmental needs to achieve these goals.  During subsequent monthly meetings, they discussed the progress made toward the identified goals.  Besides these formal meetings, the principal investigator had additional frequent informal discussions with group members on guidance, career development resources, and professional opportunities meant to strengthen a meaningful mentoring relationship. 

Society and the general public:

Students from middle schools and high schools in the surrounding Springfield and Ravenna school districts visited the principal investigator’s laboratory and learned about physics in general, and superconductivity and magnetism in particular, through demonstrations and short lectures given by the group members. In this way, the middle school and high school students were exposed to a research environment and were given a flavor of the science done in the lab and the technology involved in doing it.  We note that these school districts contain schools that have particular needs with respect to physical and life sciences instruction and that 52% and 63%, respectively, of the children served by these school districts are from families with incomes below the poverty line.  

Last Modified: 05/05/2021
Modified by: Carmen Almasan