Charge-density-wave control by adatom manipulation and its effect on magnetic nanostructures

TL;DR

This paper demonstrates how adatom manipulation with STM can reversibly control charge-density wave domains in 2H-NbSe2, affecting local electronic states and potentially enabling new control over magnetic and topological properties.

Contribution

It introduces a method to reversibly switch CDW domains using STM tip manipulation, revealing their influence on local magnetic interactions and topological states.

Findings

Reversible switching of CDW domains achieved via STM tip manipulation.

CDW domain structure influences Yu-Shiba-Rusinov state hybridization.

Potential to control topological superconductivity through CDW domain engineering.

Abstract

Charge-density waves (CDWs) are correlated states of matter, where the electronic density is modulated periodically as a consequence of electronic and phononic interactions. Often, CDW phases coexist with other correlated states, such as superconductivity, spin-density waves or Mott insulators. Controlling CDW phases may therefore enable the manipulation of the energy landscape of these interacting states. 2H-NbSe$_2$ is a prime example of a transition metal dichalcogenide (TMDC) hosting CDW order and superconductivity. The CDW is of incommensurate nature resulting in different CDW-to-lattice alignments at the atomic scale. Here, we use the tip of a scanning tunneling microscope (STM) to position adatoms on the surface and induce reversible switching of the CDW domains. We show that the domain structure critically affects other local interactions, namely the hybridization of Yu-Shiba-Rusinov (YSR) states, which arise from exchange interactions of magnetic Fe atoms with the superconductor. Our results suggest that CDW manipulation could also be used to introduce domain walls in coupled spin chains on superconductors, potentially also affecting topological superconductivity.