Quadratic nodal line phonons along high-symmetry lines in Cu3NbTe4
Purposes—To clarify the quadratic nodal line topological phonons along the high-sym-metry lines in solid materials.Methods—The first-principles calculations method based on density functional theory are used to obtain the phonon spectrum,and the phonon tight-binding Hamiltonian constructed based on force constants is used to calculate the topological properties of the material.Re-sults—The topological properties in Cu3NbTe4 are systematically studied.Quadratic band crossings are found in the high-frequency region of phonon spectrum in Cu3NbTe4.The tight-binding Hamilto-nian is used to uncover all nodes associated with the 22nd phonon band and calculate the three-dimen-sional representations of the phonon spectrum near the R point in the Brillouin zone.These quadratic nodal lines form the shape of a node cage in the Brillouin zone.Finally,the surface states and iso-fre-quency surface arcs projected on the(010)plane are calculated.Conclusions—The existence of quad-ratic nodal lines on the high-symmetry line of the solid material Cu3NbTe4 is confirmed,and its clear surface states and iso-frequency surface arcs are helpful for experimental observations.
first-principles calculationsCu3NbTe4quadratic nodal line phononssurface states
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