# Electrical Transport Interplay with Charge Density Waves, Magnetization, and Disorder Tuned by 2D van der Waals Interface Modification via Elemental Intercalation and Substitution in ZrTe3, 2H-TaS2, and Cr2Si2Te6 Crystals

## TL;DR

This paper reviews how modifying 2D van der Waals interfaces in materials like ZrTe3, 2H-TaS2, and Cr2Si2Te6 affects their electronic and magnetic properties, influencing transport behaviors.

## Contribution

The paper provides new insights into how interface modifications control coherent electronic phases and transport in 2D van der Waals materials.

## Key findings

- Modifying 2D van der Waals interfaces with heteroatoms alters phonon–electron coupling and affects charge density waves and superconductivity in ZrTe3.
- Interface modifications in Cr2Si2Te6 link in-plane resistance changes to out-of-plane ferromagnetism.
- Inserting magnetic layers in 2H-TaS2 induces anisotropic magnetism and transport responses.

## Abstract

Electrical transport in 2D materials exhibits unique behaviors due to reduced dimensionality, broken symmetries, and quantum confinement. It serves as both a sensitive probe for the emergence of coherent electronic phases and a tool to actively manipulate many-body correlated states. Exploring their interplay and interdependence is crucial but remains underexplored. This review integratively cross-examines the atomic and electronic structures and transport properties of van der Waals-layered crystals ZrTe3, 2H-TaS2, and Cr2Si2Te6, providing a comprehensive understanding and uncovering new discoveries and insights. A common observation from these crystals is that modifying the atomic and electronic interface structures of 2D van der Waals interfaces using heteroatoms significantly influences the emergence and stability of coherent phases, as well as phase-sensitive transport responses. In ZrTe3, substitution and intercalation with Se, Hf, Cu, or Ni at the 2D vdW interface alter phonon–electron coupling, valence states, and the quasi-1D interface Fermi band, affecting the onset of CDW and SC, manifested as resistance upturns and zero-resistance states. We conclude here that these phenomena originate from dopant-induced variations in the lattice spacing of the quasi-1D Te chains of the 2D vdW interface, and propose an unconventional superconducting mechanism driven by valence fluctuations at the van Hove singularity, arising from quasi-1D lattice vibrations. Short-range in-plane electronic heterostructures at the vdW interface of Cr2Si2Te6 result in a narrowed band gap. The sharp increase in in-plane resistance is found to be linked to the emergence and development of out-of-plane ferromagnetism. The insertion of 2D magnetic layers such as Mn, Fe, and Co into the vdW gap of 2H-TaS2 induces anisotropic magnetism and associated transport responses to magnetic transitions. Overall, 2D vdW interface modification offers control over collective electronic behavior, transport properties, and their interplays, advancing fundamental science and nanoelectronic devices.