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arXiv · 2003.07346

Structure and charge transport of amorphous $Cu$-doped $Ta_2O_5$ : An ab initio study

Rajendra Thapa·Bishal Bhattarai·M. N. Kozicki·Kashi N. Subedi·D. A. Drabold
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Abstract

In this paper, we present ab initio computer models of Cu-doped amorphous Ta2O5 , a promising candidate for Conducting Bridge Random Access Memory (CBRAM) memory devices, and study the structural, electronic, charge transport and vibrational properties based on plane-wave density functional methods. We offer an atomistic picture of the process of phase segregation/separation between Cu and Ta2O5 subnetworks. Electronic calculations show that the models are conducting with extended Kohn-Sham orbitals around the Fermi level. In addition to that, we also characterize the electronic transport using the Kubo-Greenwood formula modified suitably to calculate the space-projected conductivity (SPC). Our SPC calculations show that Cu clusters and under-coordinated Ta adjoining the Cu are the conduction-active parts of the network. We also report information about the dependence of the electrical conductivity on the connectivity of the Cu sub-matrix. Vibrational calculations for one of the models has been undertaken with an emphasis on localization and animation of representative modes.

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Rajendra Thapa, Bishal Bhattarai, M. N. Kozicki, Kashi N. Subedi, D. A. Drabold. 2020-03-16. Structure and charge transport of amorphous $Cu$-doped $Ta_2O_5$ : An ab initio study. https://doi.org/10.1103/physrevmaterials.4.064603

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