# Tuning from Frustrated Magnetism to Superconductivity in Quasi-One-Dimensional KCr$_3$As$_3$ Through Hydrogen Doping

## TL;DR

This study demonstrates that hydrogen intercalation effectively electron-dopes KCr$_3$As$_3$, suppressing magnetic order and inducing superconductivity, thereby establishing a charge-doped phase diagram for this quasi-one-dimensional material.

## Contribution

It reveals hydrogen doping as a new method to tune magnetic and superconducting states in KCr$_3$As$_3$, providing the first charge-doped phase diagram for these materials.

## Key findings

- Hydrogen intercalation increases H concentration in CrAs tubes.
- Charge doping suppresses magnetic order and induces superconductivity.
- Superconductivity correlates with increased hydrogen content, not crystallinity.

## Abstract

We report the charge doping of KCr$_3$As$_3$ via H intercalation. We show that the previously reported ethanol bath deintercalation of K$_2$Cr$_3$As$_3$ to KCr$_3$As$_3$ has a secondary effect whereby H from the bath enters the quasi-one-dimensional Cr$_6$As$_6$ chains. Furthermore, we find that - contrary to previous interpretations - the difference between non-superconducting as-grown KCr$_3$As$_3$ samples and superconducting hydrothermally annealed samples is not a change in crystallinity but due to charge doping, with the latter treatment increasing the H concentration in the CrAs tubes effectively electron-doping the 133 compound. These results suggest a new stoichiometry KH$_x$Cr$_3$As$_3$, that superconductivity arises from a suppressed magnetic order via a tunable parameter and pave the way for the first charge-doped phase diagram in these materials.