High-throughput calculations of magnetic topological materials

Abstract

Using magnetic band theory and topological indices obtained from Magnetic Topological Quantum Chemistry (MTQC), we have performed the first high-throughput calculations of 549 magnetic topological materials and have discovered 130 magnetic enforced semimetals and topological insulators, thereby enhancing by a factor of 10 the number of known magnetic topological materials. We use as our starting-point the Bilbao Magnetic Material Database, containing 549 non-ferromagnetic compounds whose magnetic structure and symmetry group have been painstakingly deduced from neutron-scattering experiments. This knowledge is crucial for correct ab initio calculations of the materials' band structure, which we have performed for each of those compounds -including complete phase diagrams at different values of Hubbard potential in LDA+U. Using an in-house code to be made publicly available for finding the magnetic co-representations at high symmetry points, we then feed this data into the topological machinery of MTQC to determine the topological materials, as well as the obstructed atomic limits. We then pick several candidates for showcasing new topological physics and analyze the topological trends in the materials upon varying interactions.

Band Engineering of Dirac Semimetals Using Charge Density Waves

“…Furthermore, the materials search lags behind when it comes to magnetic materials, where only a few studies with limited examples exist. [20,21] If viewed from a chemical perspective, topological band structures can be linked to delocalized chemical bonds, which often appear in compounds that are prone to undergo Peierls distortions. [22,23] For example, the Dirac cone in graphene is chemically stabilized by its delocalized, conjugated π-electrons.…”

“…Furthermore, the materials search lags behind when it comes to magnetic materials, where only a few studies with limited examples exist. [ 20,21 ]…”

Controllable quantum point junction on the surface of an antiferromagnetic topological insulator

“…In this work, we develop a theoretical prescription for the creation and manipulation of chiral edge channels on the surface of an antiferromagnetic (AFM) TI. This class of materials was introduced theoretically by Mong and Moore 26 and has recently become the focus of intense research with various candidates such as MnBi 2 Te 4 27 , MnBi 4 Te 7 28 , EuIn 2 As 2 29 and NpBi 30 appearing in the literature. Motivated by these recent developments and the fact that there is in principle no reason why both the bulk and surface gaps could not be on the order of hundreds of meV, allowing for potential high temperature device operation for certain applications, we propose and explore the properties of a robust and controllable quantum point junction (QPJ) on the surface of an AFM TI.…”

Cubic 3D Chern photonic insulators with orientable large Chern vectors

“…As an example, preserving the translational symmetry of the lattice, a Chern insulating phase is predicted in 3D to host chiral anomalous surface states (SS) on its boundary [18][19][20][21][22][23]. In contrast to 2D, a 3D Chern insulator (3D CI) is a topological phase that can be characterized by three first Chern invariants -or a Chern vector C = (C x , C y , C z ) -defined on lower dimensional surfaces [24][25][26]: such a state of matter can support chiral surface states propagating on the planes with Miller indices indicated by the Chern vector.…”