Locally noncentrosymmetric heavy-fermion compounds may produce long-sought correlated quantum phases, such as spin-triplet superconductivity with non-Abelian quasiparticles, but identifying the right candidate systems is challenging. Here, using the In flux method, we synthesize CeCoGe2 single crystals, belonging to the highly tunable pseudotetragonal (Cmcm) CeTX2 family, which allows for substitutions at both the transition metal T and at the X sites. We identify a heavy-fermion ground state with a Sommerfeld coefficient γ≈120 mJ mol−1 K−2 and a non-Fermi-liquid exponent of the electrical resistivity, which may indicate its proximity to the putative quantum critical point. However, no signs of superconductivity or magnetic order are detected down to 20 mK. Our analysis of electrical transport and structural properties indicates that coherent charge transport and the emergence of superconductivity observed under hydrostatic pressure in related compounds (CePtSi2 and CeRhGe2) are suppressed in CeCoGe2 by strong random potential scattering due to intrinsic Co vacancies (approximately 4% even in the highest-quality crystals). By tuning the growth stoichiometry and temperature profile, we demonstrate that the defect concentration can be controlled and has a pronounced effect on the residual resistivity. We hypothesize that superconductivity may be found in higher-quality CeCoGe2 crystals grown by different techniques.
@article{arxiv.2603.13111,
title = {Putative quantum critical point in locally noncentrosymmetric CeCoGe$_2$ crystals},
author = {F. Garmroudi and C. S. T. Kengle and M. H. Schenck and J. D. Thompson and E. D. Bauer and S. M. Thomas and P. F. S. Rosa},
journal= {arXiv preprint arXiv:2603.13111},
year = {2026}
}