Quantum Espresso: Studying topological insulators
Last update: 2023-10-28
A benchmark density functional theory (DFT) calculation with Quantum
Espresso has been carried out on NEC SX-Aurora TSUBASA vector computer
to obtain the electronic properties of bismuth selenide (Bi2Se3)
topological insulator.
3D Dirac cone of Bi2Se3 (PDF, 1.2 MB)
The raw data (.txt) for reproducing the 3-D linear dispersion relation
plot can be downloaded below:
TEXT Bi2Se3 Dirac cone - upper band (TXT, 32 KB)
TEXT Bi2Se3 Dirac cone - lower band (TXT, 32 KB)
Calculation details:
+ Bi2Se3(111) slab model contained 6 quintuple layers (QL),
i.e. 30 atomic monolayers,
+ Non-collinear calculation with spin-orbit coupling included,
+ Grid of 3721 k-points within the first Brillouin zone,
+ Ultra-soft pseudopotentials and local density approximation for the
exchange-correlation functional (LDA),
+ Wavefunction and density cut-offs set to 15 and 150 Ry,
respectively. NOTE: This is a test run. Production calculations
would require much larger values and proper convergence tests!
+ Total energy convergence threshold: 1.0d-6 eV.
Quantum Espresso (version 6.3) has been compiled (vectorised) with NEC
compilers (version 3.0.7) and run on 8 vector engines with MPI.
The QE code supporting SX-Aurora TSUBASA architecture:
https://github.com/SX-Aurora/QuantumEspresso
Performance notes by NEC.
https://www.nec.com/en/global/solutions/hpc/articles/tech23.html