Optical Response of 3D Model Topological Nodal-Line Semimetal

Authors

Sita Kandel, CUNY Hunter CollegeFollow
Godfrey GumbsFollow
Oleg L. Berman, CUNY New York City College of TechnologyFollow

Document Type

Book Chapter or Section

Publication Date

6-28-2023

Abstract

Wepresent a semi-analytical expression for both longitudinal and transverse optical conductivities of a model TNLSM employing the Kubo formula with emphasis on the optical spectral weight redistribution, deduced from appropriate Green’s func tions. In this semimetal, the conduction and valence bands cross each other along a one- dimensional curve protected by certain symmetry group in the 3D Brillouin zone. Although the crossing cannot be removed by any perturbations, it can be adjusted by continuous tuning of the Hamiltonian with a parameter α. When α>0, the two bands cross each other near the Γ point in the (kx,ky) plane of the first Brillouin zone making a nodal circle of radius ffiffiffi α p .Thecircle shrinks to point when α ¼ 0 and for α< 0, the nodal circle vanishes and a gap opens around Γ. Numerical results for the longitudinal optical response of such TNLSM are investigated by varying the gap due to modifying α, the chemical potential μ, temperature T and the dephasing parameter η. The longitudinal optical conductivity is anisotropic along the direction parallel or perpen dicular to the nodal ring. However, the transverse optical conductivity vanishes due to rotational symmetry.

Comments

This chapter was originally published in Advances in Nanosheets - Preparation, Properties and Applications, edited by Karthikeyan Krishnamoorthy, available at https://doi.org/10.5772/intechopen.1001440

This work is distributed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).