This award supports theoretical research and education that is motivated by experiments on unconventional superconducting materials. Superconductivity in close proximity to checkerboard charge density wave order and spin density wave order has been discovered in the underdoped cuprates; an unusual pair density wave superconductivity has been found in organic superconductors, in a cerium-cobalt-indium heavy fermion material, and also in a lanthanum cuprate material; superconductivity has been found at oxide interfaces; unexplained and puzzling physics has appeared in some Kondo lattice materials, all materials without parity symmetry. Unconventional superconductivity has been discovered in close proximity to a variety of quantum phase transitions. This research project focuses on the appearance of novel order in such materials. The PI aims to develop a new theoretical framework for pair density wave superconductors and their interplay with charge density wave and spin density wave order. The PI will further examine the appearance of new phases arising from fluctuations in pair density wave superconductors. He will examine the role of interactions in broken inversion materials applied to both bulk materials and to oxide interfaces. Theories describing the interplay between high-field quantum critical points and superconductivity with applications to specific heavy fermion materials will be developed.
This project provides educational experiences for graduate and undergraduate students and contributes to the PI?s participation in the Research Experiences for Teachers program at the University of Wisconsin ? Milwaukee and his public presentations on condensed matter physics. The PI aims to broaden participation through involving underrepresented groups in the research.
NON-TECHNICAL SUMMARY This award supports theoretical research and education that is motivated by experiments on specific materials that exhibit unusual superconducting states. Superconductivity is a cooperative electronic state of matter with remarkable properties. Among them is the ability to carry electric current without dissipation. The PI aims to develop a theoretical framework for classes of materials that show unusual superconducting states, often when superconductivity competes with magnetism or some other way electrons can spontaneously organize themselves in an ordered way. A deeper understanding of superconductivity may lead to the discovery of new superconducting materials that may be practical for dissipationless electric power transmission or novel electronic device applications.
This project provides educational experiences for graduate and undergraduate students and contributes to the PI?s participation in the Research Experiences for Teachers program at the University of Wisconsin ? Milwaukee and his public presentations on condensed matter physics. The PI aims to broaden participation through involving underrepresented groups in the research.
Normal 0 false false false EN-US X-NONE X-NONE This award supported research in the area of theoretical condensed matter physics. More specifically, research was carried out on the interactions of fermions (electrons) in systems with many fermions. Understanding these interactions in materials of fundamental and technological interest has become a central goal of condensed matter physics. These interactions lead to a wide variety of electronic phases, many of which require a deeper understanding. One well known example is unconventional superconductivity. Superconductivity is known arise when two electrons bind. This bound state requires an attractive interaction. In conventional superconductors, as opposed to unconventional superconductors, the origin of the attractive interaction between electrons is well understood: it stems from the coupling between electrons and positively ions that make up the material. In unconventional superconductors, the origin of this interaction remains unknown and is the subject of intense debate. The origin of unconventional superconductivity remains an important technological and fundamental question. This grant supported research that addressed key questions about the nature of unconventional superconductivity, superfluid and related super-solid phases, and non-trivial consequences of the coupling between the spin and momentum of electrons in materials. Some noteworthy discoveries include: a new superfluid phase comprised of bound states of six-fermions (as opposed to the usual two fermions); and a new mechanism that leads to a large electron spin response to a magnetic field in superconductors (where no such response is usually expected). This grant also supported a series of public lectures entitled "Today's Gadgets and Tomorrow's Energy: John Bardeen's Nobel Prizes" aimed at audiences aged seven to one hundred. These lectures featured audience participation and many demonstrations of the physical principles involved. Finally, this grant supported the professional training of four graduate students and one undergraduate student. This training is necessary for finding a good job at a university or in an industrial laboratory.
