turboMagnon – A code for the simulation of spin-wave spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory

Stacking-dependent topological magnons in bilayer CrI$_3$

“…Notice that the bandgaps don't occur exactly at K but are shifted to K * due to the breaking of in-plane honeycomb symmetry caused by the interlayer coupling. 29 For the ABstacking we see a shift of K − K * = (−0.005, 0.021) 2π a . In the AB'-stacking, we see shifts of (0.037, −0.019) 2π a and (0.008, −0.005) 2π a for respectively the n=2 and n=3 bands.…”

“…[27] and Ref. [29], who report bandgaps of respectively 0.30 meV and 0.47 meV. Differences might be attributed to the use of different methodologies and ab initio parameters.…”

“…Similarly, in magnetic honeycomb bilayers, a DMI-induced topological behavior of magnons is predicted, 20,[23][24][25] including the formation of Dirac magnon nodal-line loops, 23 and the opening of a topological bandgap, which contributes to a magnon Hall-and a spin Nernst effect. 20,24,25 Several recent works [26][27][28][29] attempted to characterize the magnonics of monolayer CrI 3 using ab initio calculations, and demonstrated the appearance of a small, possibly topological, bandgap caused by the spin-orbit coupling (SOC), suggesting that the material is a TMI. However, more work is required before full understanding of the magnonics in CrI 3 is achieved.…”

Twin α-trigraphyne: a new two-dimensional carbon material

“…To improve the accuracy of the calculations, hybrid functional calculations are performed using Quantum ESPRESSO. 70,71 The band gaps obtained with the Heyd–Scuseria–Ernzerhof hybrid functional are 0.26 and 0.32 eV for α-trigraphyne and twin α-trigraphyne, respectively.…”

Quantum ESPRESSO: One Further Step toward the Exascale

“…In order to show the performance of the core code of the Quantum ESPRESSO suite, PW scf , we present here calculations on a large orthorhombic supercell of chromium iodide (CrI 3 ) bulk, with 1152 atoms, 7776 electrons, and cell parameters a = 22.48 au, b / a = 1.67, and c / a = 13.86. This calculation is part of a larger study of edge magnons, − where interfaces between different crystalline phases are tested within this large supercell. The LSDA method with collinear spin polarization has been used, in combination with norm-conserving pseudopotentials generated with the atomic code, with plane-wave kinetic energy cutoff of 60 Ry.…”