# Synthesizing Weyl semimetals in weak topological insulator and topological crystalline insulator multilayers

## TL;DR

This paper introduces a novel method to create time-reversal invariant Weyl semimetals using multilayer heterostructures of trivial and nontrivial insulators, supported by theoretical models and experimental feasibility analysis.

## Contribution

It presents a new approach to synthesize Weyl semimetals through multilayer structures of topological insulators, including phenomenological explanations and low-energy models.

## Key findings

- Weyl semimetal phases with four Weyl points are theoretically demonstrated.
- Effective models confirm the existence of semimetallic phases.
- Proposed designs are feasible with current experimental techniques.

## Abstract

We propose a different route to time-reversal invariant Weyl semimetals employing multilayer heterostructures comprising ordinary "trivial" insulators and nontrivial insulators with \textit{pairs} of protected Dirac cones on the surface. We consider both the case of weak topological insualtors, where surface Dirac cones are pinned to time-reversal invariant momenta, and of topological crystalline insulators with unpinned surface Dirac cones. For both realizations we explain phenomenologically how the proposed construction leads to the emergence of a Weyl semimetal phase. We further formulate effective low-energy models for which we prove the existence of semimetallic phases with four isolated Weyl points. Finally, we discuss how the proposed design can be realized experimentally with state-of-the-art technologies.