Results for “La-Lu” | Engineering Papers

DOE OSTI2022

Computational discovery of two-dimensional rare-earth iodides: promising ferrovalley materials for valleytronics

Two-dimensional Ferrovalley materials with intrinsic valley polarization are rare but highly promising for valley-based nonvolatile random access memory and valley filter devices. These ferromagnetic materials exhibit valleys at or near the Fermi level with intrinsic magnetism. The strong coupling between magnetism and spin–orbit coupling induces intrinsic valley polarization. Using Kinetically Limited Minimization, an unconstrained crystal structure prediction algorithm, and prototype sampling based on first-principles calculations, we have discovered new Ferrovalley materials, rare-earth iodides RI 2 , where R is a rare-earth element belonging to Sc, Y, or La-Lu, and I is Iodine. The rare-earth iodides are layered and demonstrate either 2H, 1T, or 1T d phase as the ground state in bulk, analogous to transition metal dichalcogenides (TMDCs). The calculated exfoliation energy of monolayers (MLs) is comparable to that of graphene and TMDCs, suggesting possible experimental synthesis. The MLs in the 2H phase exhibit ferromagnetism due to unpaired electrons in d and f orbitals. Throughout the rare-earth series, d bands have valley polarization at K and $\overline{K}$ points in the Brillouin zone in the vicinity of the Fermi level. Large intrinsic valley polarization in the range of 15–143 meV without external stimuli is observed in these Ferrovalley materials, which can be enhanced further by applying an in-plane bi-axial strain. These valleys can selectively be probed and manipulated for information storage and processing, potentially offering superior performance beyond conventional electronics and spintronics. Here we further show that the 2H ferromagnetic phase of RI 2 MLs possesses non-zero Berry curvature and exhibits anomalous valley Hall effect with considerable anomalous Hall conductivity. Our work will incite exploratory synthesis of the predicted Ferrovalley materials and their application in valleytronics and beyond.

2D materials↗

DOE OSTI2020

Materials Data on La3Lu by Materials Project

LuLa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Lu is bonded to twelve La atoms to form LuLa12 cuboctahedra that share corners with four equivalent LuLa12 cuboctahedra, corners with eight equivalent LaLa8Lu4 cuboctahedra, edges with eight equivalent LuLa12 cuboctahedra, edges with sixteen equivalent LaLa8Lu4 cuboctahedra, faces with four equivalent LuLa12 cuboctahedra, and faces with fourteen LaLa8Lu4 cuboctahedra. There are four shorter (3.67 Å) and eight longer (3.69 Å) Lu–La bond lengths. There are two inequivalent La sites. In the first La site, La is bonded to four equivalent Lu and eight La atoms to form LaLa8Lu4 cuboctahedra that share corners with twelve equivalent LaLa8Lu4 cuboctahedra, edges with eight equivalent LuLa12 cuboctahedra, edges with sixteen LaLa8Lu4 cuboctahedra, faces with four equivalent LuLa12 cuboctahedra, and faces with fourteen LaLa8Lu4 cuboctahedra. There are four shorter (3.67 Å) and four longer (3.69 Å) La–La bond lengths. In the second La site, La is bonded to four equivalent Lu and eight equivalent La atoms to form LaLa8Lu4 cuboctahedra that share corners with four equivalent LaLa8Lu4 cuboctahedra, corners with eight equivalent LuLa12 cuboctahedra, edges with twenty-four LaLa8Lu4 cuboctahedra, faces with six equivalent LuLa12 cuboctahedra, and faces with twelve LaLa8Lu4 cuboctahedra.

36 MATERIALS SCIENCE↗