Fluctuation-induced pair density wave state in itinerant ferromagnets near to quantum criticality

Magnetic fluctuations near to itinerant ferromagnetic quantum criticality can have profound effects. It has long been realised - since the understanding of superfluidity in helium-3 - that ferromagnetic fluctuations can drive p-wave superconductivity. Near to quantum criticality, fluctuations lead to characteristic scaling with temperature and, ultimately, to a reconstruction of the phase diagram by the fluctuation-driven formation of spatially modulated magnetic order. Here, we show that near to the putative quantum critical point, these two effects become intertwined leading to a fluctuation-driven pair density wave. Moreover, describing this physics from the quantum order-by-disorder perspective reveals a fundamentally common origin of the two effects.