Physical properties of RhGe and CoGe single crystals synthesized under high pressure

TL;DR

This study characterizes RhGe and CoGe single crystals with B20 structure, revealing their metallic, paramagnetic, and semimetal properties, and highlights their potential for exploring topological fermions and surface states.

Contribution

It provides detailed physical property measurements of RhGe and CoGe B20 compounds, offering a platform for topological phase exploration and surface state studies.

Findings

Both compounds exhibit metallic behavior with Fermi-liquid scaling.

Paramagnetism confirmed in both materials.

Low carrier concentration indicates semimetallic nature.

Abstract

Chiral topological semimetals hosting multifold fermions and exotic surface states represent a frontier in topological materials research. Among them, noncentrosymmetric cubic B20 compounds-notably transition-metal silicides and germanides-offer a unique platform for realizing symmetry-protected topological phases and unconventional optoelectronic responses. Here, we report the physical properties of RhGe and CoGe single crystals with B20 structure in detail. Transport measurements reveal metallic behavior with characteristic Fermi-liquid scaling at low temperatures, while magnetization results confirm paramagnetism in both compounds. In addition, both of materials exhibit low carrier concentrations with small electronic specific heat coefficient, indicating their semimetal feature with weak electronic correlations. Such high-quality CoGe and RhGe single crystals provide a material platform to explore the evolution of multifold fermions and the instability of helicoid-arc surface states with spin-orbit coupling and surface environment in B20 material systems.