Drumhead Surface States and Topological Nodal-Line Fermions in TlTaSe2

Understand

A topological nodal-line semimetal is a new condensed matter state with one-dimensional bulk nodal lines and two-dimensional drumhead surface bands.

• Based on first-principles calculations and our effective k .
• p model, we propose the existence of topological nodal-line fermions in the ternary transition- metal chalcogenide TlTaSe2.
• The noncentrosymmetric structure and strong spin-orbit coupling give rise to spinful nodal-line bulk states which are protected by a mirror reflection symmetry of this compound.