Observation of quasi-two-dimensional Dirac fermions in ZrTe5

The presence of fast, effectively massless electrons in layered zirconium pentatelluride (ZrTe5) crystals has been confirmed. The one-atom-thick structure of graphene enables its electrons to travel much faster than typical materials, and device designers are hunting for other layered crystals that have similar ‘Dirac fermions’. By performing magneto-optical and magneto-transport measurements, Faxian Xiu from Fudan University in China and co-workers have uncovered key signatures of electrons moving at relativistic speeds in the intriguing thermoelectric material ZrTe5. Because previous investigations of this phenomenon were hampered by ZrTe5's hard-to-access Fermi level, the team used magnetic fields to induce characteristic resonance and oscillation signals. These experiments revealed that these Dirac fermions had quasi-two-dimensional behaviour and unusual interlayer characteristics, which merit further theoretical studies and exploration of possible device applications.