Discovery of a new type of topological Weyl fermion semimetal in Mo$_x$W$_{1-x}$Te$_2$
ORAL
Abstract
The Mo$_x$W$_{1-x}$Te$_2$ series hosts Type II, or strongly Lorentz-violating, Weyl fermions and is promising for novel electronics. However, the Weyl cones and Fermi arcs are predicted to sit above the Fermi level, making them strictly inaccessible to conventional ARPES. Here, we use pump-probe ARPES to image the unoccupied band structure of Mo$_x$W$_{1-x}$Te$_2$. We directly observe topological Fermi arcs. Unexpectedly, we find that certain Weyl points are close to the Fermi level, making Mo$_x$W$_{1-x}$Te$_2$ uniquely suited to transport and device applications of Weyl semimetals.
*Work at Princeton University and Princeton-led synchrotron-based ARPES measurements is supported by the U.S. Department of Energy under Basic Energy Sciences Grant No. DOE/BES DE-FG-02-05ER46200.
–