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Atomic and electronic structure of Ti substitution in Ca3Co4O9

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journal contribution
posted on 30.01.2017, 00:00 by Xuan Hu, Patrick J Phillips, Dipanjan Mazumdar, Juan Carlos Idrobo, Stanislaw Kolesnik, Arunava Gupta
We examine the role of Ti doping in the incommensurately layered thermoelectric oxide material Ca3Co4O9 (CCO). The measured Seebeck coefficient of S = 135 µV /K in Ti-doped CCO thin films of composition Ca3Co3.8Ti0.2O9 indicates no significant enhancement of S compared to pristine CCO, thus confirming prior experimental results. Using a combination of aberration-corrected scanning transmission electron microscopy, electron energy-loss spectroscopy and first-principles computations, we determine the atomic and electronic structures of Ti-doped CCO, including the preferred location of Ti dopants and valence states of Ti and Co atoms. Our findings on the structural, electronic and transport properties of the Ti-doped CCO are discussed in light of previously published results


X.H. and R.F.K. acknowledge support from the National Science Foundation (Grant No DMR-1408427). Electron microscopy research was conducted as part of a user project through Oak Ridge National Laboratory's Center for Nanophase Materials Sciences (CNMS), which is a U.S. Department of Energy Office of Science User Facility. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 (X.H., S.O.).


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© 2016 by American Institute of Physics Inc., Journal of Applied Physics


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