[Seminar] "Discrete Scale Invariance in Topological Semimetals" by Prof. Robert Joynt

[Speaker]

Prof. Robert Joynt from Kavli Institute of Theoretical Sciences, Beijing

Robert Joynt received his Ph.D. from the University of Maryland in 1982 and was a postdoctoral fellow at the Cavendish Laboratory of the University of Cambridge and the Institute for Theoretical Physics at ETH-Zurich.  Since 1986, he has been Professor of Physics at the University of Wisconsin-Madison.  He is presently on leave at the Kavli Institute for Theoretical Sciences at the Institute of Physics in Beijing.  His research has ranged from the quantum Hall effect to high-Tc superconductivity to neutron stars to quantum computing.

[Abstract]

Weyl and Dirac semimetals show anomalous quantum oscillations in the strong magnetic field (B) limit.  Very surprisingly, the oscillations are periodic in ln B.  We propose that the oscillations come from bound state spectra for Coulomb impurities that repeat when the binding energy is changed by a fixed factor, a signature of discrete scale invariance. The oscillations have now been seen in 4 Weyl semimetals: ZrTe₅, HfTe₅, TaAs, and Bi.