Phys.org  December 10, 2024 In two dimensions, a peculiar class of fermions that are massless in one direction and massive in the perpendicular direction was predicted 16 years ago. The semi-Dirac fermions remain undetected. An international team of researchers (USA – Columbia University, Pennsylvania State University, Florida State University, National High Magnetic Field Laboratory, Harvard University, Temple University, Princeton University, Flatiron Institute, the Netherlands, Spain) demonstrated the defining feature of semi-Dirac fermions in a prototypical nodal-line metal ZrSiS. Their nodal lines extended the band degeneracies from isolated points to lines, loops, or even chains in the momentum space. They pinpointed […]