Unusual Normal and Superconducting State Properties Observed in Hydrothermal Fe_1-δSe Flakes

The electronic and superconducting properties of Fe1-xSe single-crystal flakes grown hydrothermally are studied by the transport measurements under zero high magnetic fields up to 38.5 T. results contrast sharply with those previously reported for nematically ordered FeSe chemical-vapor-transport (CVT) growth. No signature nematicity, but an evident metal-to-nonmetal crossover increasing temperature, is detected in normal state present hydrothermal samples. Interestingly, a higher critical temperature Tc 13.2 K observed compared suppressed 9 presence nematicity CVT FeSe. Moreover, upper field zero-temperature limit found be isotropic respect direction reach value ~42 T, which breaks Pauli factor 1.8.