Quantum phase transition inside the superconducting dome of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ probed by optical magneto-sensing using NV-centers in diamond

K. R. Joshi, N. M. Nusran, M. A. Tanatar +6

While unusual normal state properties, such as non-Fermi liquid behavior of the resistivity, are commonly associated with strong quantum fluctuations, evidence for its presence ins…