A frozen, solid helium core, dubbed a snowball, is typically observed around cations in liquid helium. Here we discover, using path integral simulations, that around a cationic molecular impurity, protonated methane, the ${}^4\mathrm{He}$ atoms are indeed strongly localized akin to snowballs but still participate in vivid bosonic exchange induced by the rovibrational motion of the impurity. Such a combination of solidlike order with pronounced superfluid response in the first helium shell indicates that manifestations of local supersolid behavior of ${}^4\mathrm{He}$ can be induced by charged molecules.

• Received 20 January 2023
• Revised 21 July 2023
• Accepted 21 August 2023

DOI:https://doi.org/10.1103/PhysRevResearch.5.043083

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society