Kozii Vladyslav, Klein Avraham, Fernandes Rafael M, Ruhman Jonathan
Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
Department of Physics, University of California, Berkeley, California 94720, USA.
Phys Rev Lett. 2022 Dec 2;129(23):237001. doi: 10.1103/PhysRevLett.129.237001.
We study superconductivity in a three-dimensional zero-density Dirac semimetal in proximity to a ferroelectric quantum critical point. We find that the interplay of criticality, inversion-symmetry breaking, and Dirac dispersion gives rise to a robust superconducting state at the charge-neutrality point, where no Fermi surface is present. Using Eliashberg theory, we show that the ferroelectric quantum critical point is unstable against the formation of a ferroelectric density wave (FDW), whose fluctuations, in turn, lead to a first-order superconducting transition. Surprisingly, long-range superconducting and FDW orders are found to cooperate with each other, in contrast to the more usual scenario of phase competition. Therefore, we suggest that driving charge neutral Dirac materials, e.g., Pb_{x}Sn_{1-x}Te, through a ferroelectric quantum critical point may lead to superconductivity intertwined with FDW order.
我们研究了处于铁电量子临界点附近的三维零密度狄拉克半金属中的超导性。我们发现，临界性、宇称对称性破缺和狄拉克色散之间的相互作用在电荷中性点处产生了一种稳健的超导态，该点不存在费米面。利用埃利亚什贝格理论，我们表明铁电量子临界点对于铁电密度波（FDW）的形成是不稳定的，而FDW的涨落反过来又导致了一阶超导转变。令人惊讶的是，与更常见的相竞争情形相反，长程超导序和FDW序相互协作。因此，我们认为驱动电荷中性的狄拉克材料，例如PbₓSn₁₋ₓTe，通过铁电量子临界点可能会导致与FDW序相互交织的超导性。
