When a symmetry-breaking phase of matter is suppressed to a quantum critical point (QCP) at absolute zero, quantum-mechanical fluctuations proliferate. Such fluctuations can lead to unconventional superconductivity, as evidenced by the superconducting domes often found near magnetic QCPs in correlated materials. However, it remains unclear whether this superconductivity mechanism holds for QCPs of the electronic nematic phase, characterized by rotational symmetry breaking. Here, we demonstrate from systematic elastoresistivity measurements that nonmagnetic FeSe1−xTex exhibits an electronic nematic QCP showing diverging nematic susceptibility. This finding establishes two nematic QCPs in FeSe-based superconductors with contrasting accompanying phase diagrams. In FeSe1−xTex, a superconducting dome is centered at the QCP, whereas FeSe1−xSx shows no QCP-associated enhancement of superconductivity. We find that this difference is related to the relative strength of nematic and spin fluctuations. Our results in FeSe1−xTex present the first case in support of the superconducting dome being associated with the pure nematic QCP.
@article{arxiv.2202.11674,
title = {Pure nematic quantum critical point accompanied by a superconducting dome},
author = {K. Ishida and Y. Onishi and M. Tsujii and K. Mukasa and M. Qiu and M. Saito and Y. Sugimura and K. Matsuura and Y. Mizukami and K. Hashimoto and T. Shibauchi},
journal= {arXiv preprint arXiv:2202.11674},
year = {2022}
}