Anisotropic Dirac electronic structure in px,y square net system

px,y square net structure can be found in large groups of crystalline solid [1]. Especially, non-trivial Berry phase and linear dispersion derived from px,y square net in high Tc iron-pnictide structure compounds is detected in recent magneto-transport and optical experiments [2-8]. In this poster, low-energy electronic structure in ZrSiS, ZrSnTe are investigated using a first-principle calculation and a tight binding method. Without spin-orbit coupling (SOC), a closed Dirac line-node (DLN) is induced by the staggered arrangement of Zr or chalcogen ions. In this situation, Fermi surface has trivial Berry phase but non-trivial pseudospin winding number of ±2 [9]. Non-trivial Berry phase is realized after the SOC injected from the non-square net ions and electron-hole asymmetry cut and sew the FS. Quantum spin-Hall insulator phase and comparison with other square-net system [10-12] will be discussed.1