Multiple topological nodal structure in LaSb2 with large linear magnetoresistance

TL;DR

This paper reveals multiple topological nodal structures in LaSb2, including surfaces, lines, and eightfold points, confirmed by experiments, and suggests these features contribute to its large linear magnetoresistance.

Contribution

It is the first to identify and experimentally confirm multiple topological nodal structures in LaSb2, expanding understanding of topological semimetals.

Findings

Existence of topological nodal surfaces, lines, and eightfold degenerate points in LaSb2.

Confirmation of non-trivial band topology via Berry phase measurements.

Potential link between topological structures and large linear magnetoresistance.

Abstract

Unconventional fermions in the immensely studied topological semimetals are the source for rich exotic topological properties. Here, using symmetry analysis and first-principles calculations, we propose the coexistence of multiple topological nodal structure in LaSb2, including topological nodal surfaces, nodal lines and in particular eightfold degenerate nodal points, which have been scarcely observed in a single material. Further, utilizing high resolution angle-resolved photoemission spectroscopy in combination with Shubnikov-de Haas quantum oscillations measurements, we confirm the existence of nodal surfaces and eightfold degenerate nodal points in LaSb2, and extract the {\pi} Berry phase proving the non-trivial electronic band structure topology therein. The intriguing multiple topological nodal structure might play a crucial role in giving rise to the large linear magnetoresistance. Our work renews the insights into the exotic topological phenomena in LaSb2 and its analogous.