Zhao et al. Reply

Abstract

Zhao et al. Reply In the first sentence of the Comment [1], the authors refer to four systems: GaNð10 10Þ-1H, ZnOð10 10Þ-1H, GaNð10 10Þ-Li, and ZnOð10 10Þ-1Li. In the second sentence, the authors claim to demonstrate that "a charge-density-wave (CDW) phase is due to the artifact of the generalized gradient approximation (GGA), while the antiferromagnetic (AFM) ground state is predicted by the hybrid DFT calculation…" The Comment contains a single table, showing the total energy of the GaNð10 10Þ-1H system only. No numerical results were presented for the other three systems. It is not clear how the authors arrived at their very general conclusion.We have checked the validity of Kim et al.'s claim by performing new calculations using two popular hybrid functionals, HSE06 [2,3] and B3LYP [4], on the four systems mentioned in the Comment. These two hybrid functional methods are generally considered to be at the same level of accuracy. All hybrid functional calculations are performed on a 12-layer slab separated by a 12 Å vacuum. The two-dimensional k grid of the Brillouin zone is 8 × 6 for the pð1 × 1Þ cell and the same density is used for larger cells. The results are listed below.Based on these results, we draw a few observations: (i) For the GaNð10 10Þ-1H system, different hybrid functionals produce different ground states. The conclusions are not consistent. Our Table I shows that the B3LYP hybrid method favors the CDW state by 0.21 eV per pð2 × 2Þ unit cell, and that this preference is reversed with the HSE06 hybrid method, which instead favors the AFM state by 0.06 eV. This is similar to Kim's HSE results, which also favored the AFM state by 0.07 eV. Importantly, Kim et al. also perform RPA calculations, which favor the AFM state by 122 meV per pð2 × 2Þ unit cell in GaN-1H. We have confirmed this value for RPA. For the GaNð10 10Þ-1Li system, however, both hybrid functionals B3LYP and HSE06 favor the CDW ground state, by 0.5 and 0.25 eV, respectively. For GaNð10 10Þ-1Li, we have also carried out RPA calculations [5-8] using a four-layer slab. The RPA results favor the CDW state over the AFM state by 0.16 eV. Thus, for GaNð10 10Þ-1Li, all results using B3LYP, HSE06 and RPA support our findings [9], and disagree with the claim of Kim et al. (ii) For ZnOð10 10Þ with 1H and 1Li, both HSE06 and B3LYP functionals favor the CDW ground state, according to our new results shown

Superconductivity and hybrid soft modes inTiSe2

“…[43] Intercalation with Cu atoms shifts the chemical potential of 1T-TiSe 2 by 0.1 eV. [53,54] Since the circumstances in the pristine material are nearly ideal for the formation of excitons, they deteriorate quickly upon intercalation, leaving a dominant role for the phonons in the CDW formation in this part of the phase diagram. As explained above, such a scenario naturally leads to a superconducting dome centered around the critical value of intercalation.…”

Comment on “Quasi-One-Dimensional Metal-Insulator Transitions in Compound Semiconductor Surfaces”

“…The further lattice relaxation of p(2×2) gives ∆E = −0.57 eV and E g = 0.99 eV. Interestingly, a ferromagnetic (FM) phase appears in metallic p(1×1), but such spin ordering disappears in semiconducting p(1×2) and p(2×2) [1]. This disappearance of magnetic order may be due to the fact that the local density approximation or GGA tends to stabilize artificially delocalized electronic states due to their inherent self-interaction error (SIE) [2].…”

“…For the 1D metallic structure composed of the surface metal atoms (Ga or Zn), Zhao et al [1] found that the semiconducting p(1×2) phase with alternately up-and-down displacements is more stable than the metallic p(1×1) phase, and the p(2×2) phase is further stabilized. The relative total energies (∆E) of these phases for GaN(1010)-1H are listed in Table I.…”

“…For GaN(1010)-1H, Zhao et al [1] showed that the p(1×1) phase has a Fermi surface nesting that drives the CDW with the up-down buckling distortion. The resulting Peierls-type MI transition produced the p(1×2) phase with ∆E = −0.51 eV and E g = 0.74 eV (see Table I).…”

“…Based on density-functional theory (DFT) calculations within the generalized gradient approximation (GGA), Zhao et al [1] claimed that one-atom-wide metallic structures formed by selectively bonding of H or Li atoms to GaN(1010) and ZnO(1010) undergo the Peierls-type metal-insulator (MI) transitions, leading to a charge-density-wave (CDW) formation with periodic lattice distortion. However, we here demonstrate that such a CDW phase is due to the artifact of the GGA, while the antiferromagnetic (AFM) ground state is predicted by the hybrid DFT calculation and the exact-exchange plus correlation in the random-phase approximation (EX + cRPA).…”