First-Principles Study on the Electronic and Mechanical Properties of the Cr(001)/Al(001) Structure.

Abstract

We utilized spin-polarized density functional theory to analyze the properties of the Cr(001)/Al(001) structure. The interface was classified into three forms-bcc, bridge, and top-based on the bonding coordinates between Cr and Al atoms. The total density of states (DOS) of the structures is mainly influenced by the Cr (d) orbitals. The local DOS of the Cr atoms at the interface exhibits slight variations based on their coordination with neighboring Al atoms. The mechanical properties of a specific layer were analyzed by using the rigid grain shift (RGS) method, and the properties of all layers were analyzed by using the homogeneous lattice extension method. Our results confirmed that the bonding strength, as determined by the RGS method, follows a decreasing order from the strongest to the weakest: bcc, bridge, and top. We applied uniform deformation to the entire system in the thickness direction and allowed it to relax: we observed that deformation occurs mainly in the Al region and ultimately leads to failure regardless of the type of interface. Consequently, similar strain-stress curves were observed in all Cr(001)/Al(001) structures. The failure in the Al region is attributed to the lower stiffness of the Al-Al layers compared to the top interface despite the lower work of separation for the top interface.