Title: NMR evidence for static local nematicity and its cooperative interplay with low-energy magnetic fluctuations in FeSe under pressure,
Abstract: We present $^{77}$Se-NMR measurements on single-crystalline FeSe under
pressures up to 2 GPa. Based on the observation of the splitting and broadening
of the NMR spectrum due to structural twin domains, we discovered that static,
local nematic ordering exists well above the bulk nematic ordering temperature,
$T_{\rm s}$. The static, local nematic order and the low-energy stripe-type
antiferromagnetic spin fluctuations, as revealed by NMR spin-lattice relaxation
rate measurements, are both insensitive to pressure application. These NMR
results provide clear evidence for the microscopic cooperation between
magnetism and local nematicity in FeSe.