Pure nematic quantum critical point accompanied by a superconducting dome.

Ishida, Kousuke; Onishi, Yugo; Tsujii, Masaya; Mukasa, Kiyotaka; Qiu, Mingwei; Saito, Mikihiko; Sugimura, Yuichi; Matsuura, Kohei et al. · Proc Natl Acad Sci U S A · 2022

basic_science · Level V

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Abstract

SignificanceThe notion of the quantum critical point (QCP) is at the core of modern condensed matter physics. Near a QCP of the symmetry-breaking order, associated quantum-mechanical fluctuations are intensified, which can lead to unconventional superconductivity. Indeed, dome-shaped superconducting phases are often observed near the magnetic QCPs, which supports the spin fluctuation-driven superconductivity. However, the fundamental question remains as to whether a nonmagnetic QCP of electronic nematic order characterized by spontaneous rotational symmetry breaking can promote superconductivity in real materials. Here, we provide an experimental demonstration that a pure nematic QCP exists near the center of a superconducting dome in nonmagnetic FeSe[Formula: see text] Te<i><sub>x</sub></i>. This result evidences that nematic fluctuations enhanced around the nematic QCP can boost superconductivity.