\section*{Acknowledgments}
	THz spectroscopy work was supported by National Science Foundation 1905981 (M.M.).
	THz MDCS instrument was supported by the W.M. Keck Foundation (initial design and commission) and by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Superconducting Quantum Materials and Systems Center (SQMS) under the contract No. DE-AC02-07CH11359 (upgrade for improved cryogenic operation).
	THz spectral analysis was supported by the Ames Laboratory, the US Department of Energy, Office of Science,
	Basic Energy Sciences, Materials Science and Engineering Division under contract No. DEAC0207CH11358 (L.L.). 
	The work at UW-Madison (synthesis and characterizations of epitaxial thin films) was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), under award number DE-FG02-06ER46327.
	Modeling work at the University of Alabama, Birmingham was supported by the US Department of Energy under contract \# DE-SC0019137 and was made possible in part by a grant for high performance computing resources and technical support from the Alabama Supercomputer Authority.
	
		


	











	
	
	\clearpage
	








	
\end{document}




















