Topologically nontrivial electronic states in CaSn3

Abstract

Based on the first-principles calculations, we theoretically propose topologically non-trivial states in a recently experimentally discovered superconducting material CaSn 3 . When the spin-orbit coupling (SOC) is ignored, the material is a host to three-dimensional topological nodal-line semimetal states. Drumhead like surface states protected by the coexistence of time-reversal and mirror symmetry emerge within the two-dimensional regions of the surface Brillouin zone connecting the nodal lines. When SOC is included, unexpectedly, each nodal line evolves into two Weyl nodes (W1, W2) in this centrosymmetric material. Berry curvature calculations show that these nodes occur in a pair and act as either a source or sink of Berry flux. The material also has unique surface states in the form of Fermi arcs, which unlike other known Weyl semimetal, form closed loops of surface states on the Fermi surface. Our theoretical realization of topologically nontrivial states in a superconducting material paves the way towards unraveling the interconnection between topological physics and superconductivity.

de Haas-van Alphen Quantum Oscillations in BaSn3 Superconductor with Multiple Dirac Fermions*

“…Up to now, the physical properties of ASn 3 have been less studied as compared with LnM 3 . The recent studies on CaSn 3 have revealed it as a weakly coupled type-II superconductor hosting eight pairs of WPs in the BZ with closed loops of surface Fermi arcs [47][48][49]. In light of the intriguing properties of CaSn 3 , investigation on the analogue BaSn 3 in terms of the electronic structure to examine possible nontrivial topological states is very valuable.…”

Topological Phase Transition in Sb2Mg3 Assisted by Strain

“…Herein, we propose one of the simplest ways to realize a binary heavy element based on a closed-shell semiconductor with an alkaline earth element. 13,17,44,50,51 Investigations on Dirac materials are very interesting for quantum property studies. Similarly, studies of stanene functionalized films, 43,52 Nb 2 O 3 , 53 arsenene, 54 2D Mn-cyanogen, 55 and Bi/Sb (111) films 56 are in good agreement with previous studies.…”

“…8−12 Contrarily, Dirac semimetals (DSMs) touch the Fermi level in the band structure calculation. 13−17 The bulk band gap of nontrivial topology can be closed, and therefore, the energy level of the topologically protected metallic bulk states is critical in a topological quantum phase transition (TQPT). This has been enhanced by tuning an intrinsic material property such as SOC interaction by chemical doping or alloying of the composition.…”

Advances in synthetic gauge fields for light through dynamic modulation

“…When only T-symmetry is broken, the minimum number of pairs of Weyl points is one. There has been a massive effort devoted to investigating Weyl points and their associated phenomena in electronic systems, including Fermi arc surface states [72][73][74][75] and chiral anomalies [76][77][78][79][80][81]. Weyl points have also been found in photonic crystals [82][83][84][85][86][87][88], as well as acoustic [89,90] and plasmonic structures [91].…”