Beryllium carbide as diffusion barrier against Cu: First-principles study<xref rid="cpb_29_1_016601fn1" ref-type="fn">*</xref><fn id="cpb_29_1_016601fn1"><label>*</label><p>Project supported by the National Natural Science Foundation of China (Grant Nos. 11974253 and 11774248) and the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (Grant No. 2017YFA0303600).</p></fn>

Beryllium carbide as diffusion barrier against Cu: First-principles study**

Project supported by the National Natural Science Foundation of China (Grant Nos. 11974253 and 11774248) and the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (Grant No. 2017YFA0303600).

Cao Hua-Liang¹, Cheng Xin-Lu^{1, 2}, Zhang Hong^{1, 2, †}

The five interstitial sites of copper atom are in the crystal of beryllium: trigonal interstitial site (Tr), and hexahedral site (Hx) in the base plane; octahedral site (Oc), tetrahedral site (Te), and non-basal trigonal interstitial site (NBt) in the non-base plane.