Topological insulators (TIs) are an exciting new type of material that on their surface carry electric current, but within their bulk, act as insulators. Since the discovery of TIs about a decade ago, their unique characteristics (which point to potential applications in quantum computing) have been explored theoretically, and in the last five years, experimentally.
But where in theory, the bulk of TIs carry no current, in the laboratory, impurities and disorder in real materials mean the bulk is, in fact, conductive. This has proven an obstacle to experimentation with TIs: findings from prior experiments designed to test the surface conductivity of TIs unavoidably included contributions from the surplus of electrons in the bulk.
Now an interdisciplinary research team at the University of Illinois at Urbana-Champaign, in collaboration with researchers at Brookhaven National Laboratory’s Condensed Matter Physics and Materials Science Department, has measured superconductive surface states in TIs where the bulk charge carriers were successfully depleted.
Physics Illinois takes great pride in the dedication, professionalism, and plain hard work of the scholars that meet one of our core missions—teaching. Each semester, the University's Center for Teaching Excellence polls our toughest critics—the students who take Physics classes—and asks them to assess the skills and effectiveness of their teachers. Only the very best make this list.
An interdisciplinary team of scientists, led by Swanlund Professor of Physics Nigel Goldenfeld, is exploring the earliest stages of evolution as part of a new NASA Astrobiology Institute (NAI) initiative at the University of Illinois. The researchers believe that early evolution involved the sharing of genes among a community of organisms, rather than parent-to-offsping genetic transfer. "We are hoping to find fossils of the collective state in the genomes of organisms," Goldenfeld says.
Phillips’ group works on the theory behind high-temperature superconductors. In superconductors, current flows freely without resistance. Cuprate superconductors have puzzled physicists with their superconducting ability since their discovery in 1987.
The researchers developed a model outlining the breakdown of Luttinger’s theorem that is applicable to cuprate superconductors, since the hypotheses that the theorem is built on are violated at certain energies in these materials. The group tested it and indeed found discrepancies between the measured charge and the number of mobile electrons in cuprate superconductors, defying Luttinger.
An announcement today by CERN scientists speaking from the Moriond Conference in La Thuile, Italy, generated media attention around the globe; the scientists affirmed the greatly celebrated particle discovery announced last summer on July 4 by both the ATLAS and CMS experiments looks strikingly like a Higgs boson, though it is too early to confirm that it is the single Higgs boson of the standard model of physics. It might still be one of a family of Higgs bosons predicted in “beyond the standard model” theories.
University of Illinois high energy physicists Steven Errede, Deborah Errede, Tony Liss, and Mark Neubauer, along with their many team members—postdocs, graduate students, and undergraduate students—have worked with the ATLAS collaboration since 1994, contributing substantially to the design, building, commissioning, data taking, and data analysis at the ATLAS experiment at CERN.
Liss said, "This is an important milestone because it represents the full dataset from the last year of running. But the case is not closed yet on whether this is the standard model Higgs. We have more work to do."
Physics Illinois professors Lance Cooper and Philip Phillips are listed among the American Physical Society's outstanding referees for 2013. The Outstanding Referee program was instituted in 2008 to recognize scientists who have been exceptionally helpful in assessing manuscripts for publication in the APS journals. By means of the program, APS expresses its appreciation to all referees, whose efforts in peer review not only keep the standards of the journals at a high level, but in many cases also help authors to improve the quality and readability of their articles – even those that are not published by APS.
The American Association for the Advancement of Science awarded Frolov the 2012 Newcomb Cleveland Prize, which recognizes the best research paper of the year published in the association's prestigious journal Science. The award comes with $25,000 for Frolov and five collaborators, three at Delft University of Technology and two at Eindhoven University of Technology, both in the Netherlands.
Three professors at the University of Illinois at Urbana-Champaign have been selected to receive 2013 Sloan Research Fellowships from the Alfred P. Sloan Foundation. Asst. Professor Taylor Hughes is interested in condensed matter systems, working with materials such as superconductors, topological insulators and graphene. In recent work he has used quantum entanglement to characterize exotic phases of matter. For example, recent research explored topological insulators – materials that conduct electricity only on their surface, and with very little energy dissipation – using quantum entanglement to describe the quantum properties of these materials. He also looks at the increasing role that quantum effects play in nanotechnology devices.