Wannier90 is an open-source computer program for calculating maximally-localised Wannier functions (MLWFs) from a set of Bloch states. It is interfaced to many widely used electronicstructure codes thanks to its independence from the basis sets representing these Bloch states. In the past few years the development of Wannier90 has transitioned to a community-driven model; this has resulted in a number of new developments that have been recently released in Wannier90 v3.0. In this article we describe these new functionalities, that include the implementation of new features for wannierisation and disentanglement (symmetry-adapted Wannier functions, selectivelylocalised Wannier functions, selected columns of the density matrix) and the ability to calculate new properties (shift currents and Berry-curvature dipole, and a new interface to many-body perturbation theory); performance improvements, including parallelisation of the core code; enhancements in functionality (support for spinor-valued Wannier functions, more accurate methods to interpolate quantities in the Brillouin zone); improved usability (improved plotting routines, integration with arXiv:1907.09788v1 [cond-mat.mtrl-sci]

We investigate electronic structures of LaMO 3 ͑M =Tiϳ Cu͒ systematically by means of U + GW approximation. In these strongly correlated systems, it is important to treat large on-site Coulomb interactions and their dynamical screening effects. Transition-metal ions in perovskite-type lanthanum oxides are trivalent and their physics is qualitatively different from that of divalent transition-metal ions in transition-metal mono-oxides. The localization of wave functions of La 4f and 3d orbitals of Ti, V, and Co is crucial. On the other hand, the screening effect for other transition-metal 3d orbitals is strong enough so as to reduce the on-site staticscreened Coulomb interaction in trivalent oxides. The band gaps, the magnetic moments, and energy spectra are discussed in comparison with the experimentally observed results. Calculated energy spectra of LaMO 3 ͑M =Vϳ Cu͒ are in good agreement with experimental results.

We study the properties of a family of anti-pervoskite materials, which are topological crystalline insulators with an insulating bulk but a conducting surface. Using ab-initio DFT calculations, we investigate the bulk and surface topology and show that these materials exhibit type-I as well as type-II Dirac surface states protected by reflection symmetry. While type-I Dirac states give rise to closed circular Fermi surfaces, type-II Dirac surface states are characterized by open electron and hole pockets that touch each other. We find that the type-II Dirac states exhibit characteristic van-Hove singularities in their dispersion, which can serve as an experimental fingerprint. In addition, we study the response of the surface states to magnetic fields.Topological crystalline insulators (TCIs) are insulating in the bulk, but exhibit conducting boundary states protected by crystal symmetries [1][2][3]. As opposed to surface states of ordinary insulators, the gapless modes at the surface of TCIs arise due to a non-trivial topology of the bulk wavefunctions, which is characterized by a quantized topological invariant, e.g., a mirror Chern or mirror winding number [4][5][6]. One prominent example of a TCI is the rocksalt semiconductor SnTe [7][8][9][10], which supports at its (001) surface four Dirac cones protected by reflection symmetries. The surface modes of this and all other known TCIs are of the standard Dirac fermion type with closed point-like (or circular) Fermi surfaces, which we refer to as "type-I". However, as we discuss in this article, crystal symmetries can also give rise to other types of surface fermions.In particular, we show that at certain surfaces of the anti-perovskite materials A 3 EO [11][12][13][14][15][16] there exist so called "type-II" Dirac points which are protected by reflection symmetry. (Here A denotes an alkaline earth metal, while E stands for Pb or Sn.) These type-II band crossings do not lead to circular Fermi surfaces, but rather give rise to open electron and hole pockets that touch each other. This is reminiscent of the type-II Weyl points that have recently been predicted to exist in WTe 2 [17][18][19][20] and LaAlGe [21]. Here, however, these type-II band crossings occur at the surface rather than in the bulk of the material. As a consequence, the surface physics of A 3 EO is radically different to the one of standard TCIs with point-like Dirac surface states. This pertains in particular to the surface magneotransport.Using first-principles calculations and a tight-binding model, we systematically study the surface states of A 3 EO, with a particular focus on Ca 3 PbO, which crystallizes in its low-temperature phase in the cubic space group Pm3m. We find that the (011) surface exhibits type-II Dirac nodes, whereas the (111) surface supports both type-I and type-II Dirac states. On the (001) surface, on the other hand, the Dirac nodes overlap with the bulk bands. All these surface states are protected by the crystal symmetries of A 3 EO, in particular the reflection symmetr...

A GW approximation ͑GWA͒ method named U + GWA is proposed, where we can start GWA with more localized wave functions obtained by the local spin-density approximation ͑LSDA͒ + U method. Then GWA and U + GWA are applied to MnO, NiO, and V 2 O 3 in antiferromagnetic phase. The band gaps and energy spectra show excellent agreement with the experimentally observed results and are discussed in detail. The calculated width of d bands of V 2 O 3 is much narrower than that of the observed one which may be a mixture of t 2g 2 multiplet and single-electron t 2g level. GWA or U + GWA does not work also in the paramagnetic phase of V 2 O 3 and the reason for this is clarified. The method of the unique choice of on-site Coulomb interaction is discussed in detail. The criterion for whether we should adopt GWA or U + GWA is discussed and is assessed with the help of the off-diagonal elements of the self-energy.

We present ab initio GW plus cumulant-expansion calculations for an organic compound (TMTSF)2PF6 and a transition-metal oxide SrVO3. These materials exhibit characteristic lowenergy band structures around the Fermi level, which bring about interesting low-energy properties; the low-energy bands near the Fermi level are isolated from the other bands and, in the isolated bands, unusually low-energy plasmon excitations occur. To study the effect of this low-energyplasmon fluctuation on the electronic structure, we calculate spectral functions and photoemission spectra using the ab initio cumulant expansion of the Green's function based on the GW self-energy. We found that the low-energy plasmon fluctuation leads to an appreciable renormalization of the low-energy bands and a transfer of the spectral weight into the incoherent part, thus resulting in an agreement with experimental photoemission data.