Fig. 3: 3D atomic metal-oxide interfaces.
From: Three-dimensional atomic insights into the metal-oxide interface in Zr-ZrO2 nanoparticles
a–d 3D surface renderings of three major phases, showing the contour (a) of metal core (red), c-ZrO2 (green) and a-ZrO2 (blue) of Zr1. Three planes go through the Zr1 in different directions. The sliced atomic models (4-atom-layers thick) highlights three different types of interfaces, i.e., metal/c-ZrO2 semicoherent interface between (b; in blue frame), metal/c-ZrO2 incoherent interface (c; in green frame), and metal/a-ZrO2 incoherent interface (d; in orange frame). e–g Experimental semicoherent interface structures specified by the rectangle region in (b). e The semicoherent interface viewing from metal [\(1\bar{1}0\)] direction. There is a bending of ≈ 11° between metal and interfacial layers in metal [112] direction (angle between red line and blue line), and a bending of ≈ 8° between interfacial layers and c-ZrO2 in oxide [110] direction (angle in blue line and ivory line). The coordination tripods in red and ivory boxes shows the spatial crystal orientation of metal and oxide, respectively. f The semicoherent interface viewing from metal [101] direction (by rotating the cutout in (e) 120° counter clockwise), showing a twisting of ≈ 4° in metal [\(1\bar{1}0\)] direction (angle between red line and ivory line). g One atomic plane extracted from the semicoherent interface (the highlighted area in red in e), viewing from metal [\(\bar{1}\bar{1}1\)] direction. In this direction, the oxide shows the (002) plane. The color of the atomic bonding shows the Zr-Zr bond length. h The ideal model of an interface structure between ideal FCC Zr metal and ideal cubic ZrO2, showing a 15° of wedge if no bending exists. To minimize the interfacial energy and maintain the coherency, a bending of 15° (i) is needed. The structure changed from metal to oxide shows in (j). The oxygen atoms are colored in red. k, l Incoherent interface structures specified by the rectangle region in (c, d), showing the metal/c-ZrO2 (k) and metal/a-ZrO2 interface (l). In (e–l), the metal atoms, interface atoms and oxide atoms are colored in deep red, blue and ivory, respectively. The Zr atoms are bonded with their first-nearest Zr neighbors and linked with lines (Methods).
