Emergent topology in thin films of nodal line semimetals

Abstract

We investigate finite-size topological phases in thin films of nodal line semimetals (co-dimension 2) in three dimensions. By analyzing the hybridization of drumhead surface states, we demonstrate that such systems can transition into either a lower-dimensional nodal line state (co-dimension 1) or a fully gapped trivial phase. Additionally, we explore the hybridization of bulk states along the nodal loop when the system is finite in directions parallel to the loop's plane. This generally results in a topologically nontrivial gap. In films finite along a single in-plane direction, a partial gap opens, giving rise to two-dimensional Weyl cones characterized by a one-dimensional $\mathbb{Z}$ invariant. When the system is finite along both in-plane directions, a fully gapped phase appears, distinguished by a $\mathbb{Z}$ invariant whose value increases with film thickness. We further discuss the bulk-boundary correspondence associated with these emergent topological phases.

Updated version (10 pages, 5 figures)

References in corpus (17)

• Discovery of topological Weyl fermion lines and drumhead surface states in a room temperature magnet
• Finite size effects of helical edge states in HgTe/CdTe quantum wells
• Classification of reflection symmetry protected topological semimetals and nodal superconductors
• Multichannel Generalization of Kitaev's Majorana End States and a Practical Route to Realize Them in Thin Films
• New Family of Robust 2D Topological Insulators in van der Waals Heterostructures
• Topological surface electronic states in candidate nodal-line semimetal CaAgAs
• Magnetized Topological Insulator Multilayers
• Two-dimensional topological insulator state in cadmium arsenide thin films
• Evidence of topological nodal lines and surface states in the centrosymmetric superconductor SnTaS2
• Zeeman field-induced two-dimensional Weyl semimetal phase in cadmium arsenide
• Finite-size Topology
• Time-reversal invariant finite-size topology
• Quantum Hall effect induced by chiral Landau levels in topological semimetal films
• Finite-size topological phases from semimetals
• Theory for Cd${}_3$As${}_2$ thin films in the presence of magnetic fields
• Noncentrosymmetric two-dimensional Weyl semimetals in porous Si/Ge structures
• Interfaces of nodal-line semimetals: drum states, transport and refraction