2017/03/12 by Bahadur Singh, Xiaoting Zhou, Hsin Lin +1
Materials Science · Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Band gap #Combinatorics #Condensed matter physics #Geometry #Graphene research and applications #Line (geometry) #Mathematics #Physics #Saddle point #Semimetal #Surface (topology) #Surface states #Topological Materials and Phenomena #Topological insulator #Topology (electrical circuits) #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.97.075125
published as Phys. Rev. B 97, 075125 (2018) · 4 figures
arxiv created 2017/03/12 · openalex created_date 2017/04/07 · openalex publication_date 2018/02/13 · arxiv updated 2018/02/21 · openalex updated_date 2026/08/05
Topological nodal-line semimetals are exotic conductors that host symmetry-protected conducting nodal lines in their bulk electronic spectrum and nontrivial drumhead states on the surface. Based on first-principles calculations and an effective model analysis, we identify the presence of topological nodal-line semimetal states in the low crystalline symmetric TT^\ensuremath'X family of compounds (T,T^\ensuremath' = transition metal, X= Si or Ge) in the absence of spin-orbit coupling (SOC). Taking ZrPtGe as an exemplar system, we show that owing to small lattice symmetry this material harbors a single nodal line on the ky=0 plane with large energy dispersion and unique drumhead surface state with a saddlelike energy dispersion. When the SOC is included, the nodal line gaps out and the system transitions to a strong topological insulator state with Z2=(1;000). The topological surface state evolves from the drumhead surface state via the sharing of its saddlelike energy dispersion within the bulk energy gap. These features differ remarkably from those of the currently known topological surface states in topological insulators such as Bi2Se3 with Dirac-cone-like energy dispersions.