Comparison of Nematic Electronic Structure in the ``Parent States'' of Ca(Fe$_{1-x}$Co$_{x})_{2}$As$_{2}$ and of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$

The mechanism of high-temperature superconductivity in both the cuprate and iron-based superconductors is unresolved. We use spectroscopic imaging STM to compare the electronic structure of representative compounds Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$ and CaFe$_{1.94}$Co$_{0.06}$As$_{2}$-- both in the `parent' state from which this superconductivity emerges. Evidence for fundamental electronic nematicity in both these systems will be presented and discussed.\footnote{In collaboration with: T.-M. Chuang, Cornell University, Florida State University; M.P. Allan, Cornell University, University of St. Andrews; Jinho Lee, Cornell University, Brookhaven National Laboratory; Yang Xie, Cornell University; Ni Ni, S.L. Bud'ko, Ames Laboratory U.S. DOE and Iowa State University; G.S. Boebinger, Florida State University; P.C. Canfield, Ames Laboratory U.S. DOE and Iowa State University; M. J. Lawler, Cornell University, Binghamton University; K. Fujita, Cornell University, Brookhaven National Laboratory, University of Tokyo; Jhinhwan Lee, A.R. Schmidt, Cornell University, Brookhaven National Laboratory; Y. Kohsaka Cornell University, Brookhaven National Laboratory, RIKEN; Chung Koo Kim, Cornell University, Brookhaven National Laboratory; H. Eisaki, Institute of Advanced Industrial Science and Technology; S. Uchida, University of Tokyo; J.P. Sethna, Eun-Ah Kim, Cornell University.}