No abstract

We present a general scheme of range-separated hybrid functionals in which the mixing parameters of Fock exchange are fully nonempirical and determined solely from the dielectric function.We showthat the full dielectric dependence leads to an unscreened Fock exchange in the short range, while in the long range the Fock exchange is correctly screened by the macroscopic dielectric constant. The range separation is obtained by fitting to the calculated static dielectric function in the long-wavelength limit. The resulting hybrid functional accurately accounts for electronic and structural properties of various semiconductors and insulators spanning a wide range of band gaps. We present a general scheme of range-separated hybrid functionals in which the mixing parameters of Fock exchange are fully nonempirical and determined solely from the dielectric function. We show that the full dielectric dependence leads to an unscreened Fock exchange in the short range, while in the long range the Fock exchange is correctly screened by the macroscopic dielectric constant. The range separation is obtained by fitting to the calculated static dielectric function in the long-wavelength limit. The resulting hybrid functional accurately accounts for electronic and structural properties of various semiconductors and insulators spanning a wide range of band gaps.

We determine the band alignment between various semiconductors and liquid water by combining molecular dynamics (MD) simulations of atomistic interface models, electronic-structure calculations at the hybrid-functional and GW level, and a computational standard hydrogen electrode. Our study comprises GaAs, GaP, GaN, CdS, ZnO, SnO 2 , rutile TiO 2 , and anatase TiO 2 . For each semiconductor, we generate atomistic interface models with liquid water at the pH corresponding to the point of zero charge. The molecular dynamics are started from two kinds of initial configurations, in which the water molecules are either molecularly (m) or dissociatively (d) adsorbed on the semiconductor surface. The calculated band offsets are found to be strongly influenced by the adsorption mode at the semiconductor−water interface, leading to differences larger than 1 eV between m and d models of the same semiconductor. We first assess the accuracy of various ab initio electronic-structure schemes. The use of a standard hybrid functional leads to large errors for the conduction band edge but nevertheless accounts accurately for the position of the valence band edge. One-shot GW calculations with a starting point at the semilocal density functional level do not yield any improvement. It is necessary to turn to one-shot GW calculations based on a hybrid-functional starting point to achieve a noticeable improvement in the determination of the band edges, with mean average errors ranging between 0.23 and 0.27 eV. The use of state-of-the-art quasiparticle self-consistent GW schemes does not lead to any further improvement for the set of semiconductors under investigation. Further improvement with mean average errors of 0.20 eV is obtained when turning to hybrid-functional and GW methods, in which the experimental band gap of the semiconductor is enforced by construction. The present work sets a benchmark for the accuracy by which band edges at semiconductor−water interfaces can be obtained with current advanced electronic-structure methods. In particular, the importance of providing an atomistic description of the semiconductor−water interface is emphasized.

We construct hybrid functionals in a nonempirical way by fixing the fraction of Fock exchange through either the long-range screening or the generalized Koopmans' condition applied to defect charge-transition levels. These functionals not only give band gaps of solids as accurate as state-of-the-art GW calculations, but are also capable of describing polaronic distortions. The Koopmans' condition is found to be satisfied across a series of defects, to the point of achieving accurate band gaps through a hydrogen probe. Extension to range-separated functionals demonstrates the robustness of the present approach.

Our results suggest that miR-92a-3p regulates cartilage development and homeostasis, which directly targets HDAC2, indicating histone hyperacetylation plays an important role in increased expression of cartilage matrix.

Self-consistent GW calculations with efficient vertex corrections are employed to determine the electronic structure of liquid water. Nuclear quantum effects are taken into account through ab initio pathintegral molecular dynamics simulations. We reveal a sizable band-gap renormalization of up to 0.7 eV due to hydrogen-bond quantum fluctuations. Our calculations lead to a band gap of 8.9 eV, in accord with the experimental estimate. We further resolve the ambiguities in the band-edge positions of liquid water. The valence-band maximum and the conduction-band minimum are found at −9.4 and −0.5 eV with respect to the vacuum level, respectively. DOI: 10.1103/PhysRevLett.117.186401 Liquid water is such a ubiquitous substance that it has been the subject of upsurging research efforts for the past 30 years. Of particular importance is the electronic structure of liquid water, the significance of which has been recently highlighted in clean-energy technologies through semiconductor-assisted artificial photosynthesis [1,2]. A good understanding of the electronic structure of water is a prerequisite toward the design of photocatalytic systems with high catalytic activity.The extended hydrogen-bond network of liquid water gives rise to the formation of electronic bands. The valence band maximum (VBM) is characterized by the localized 2p z electrons of O atoms. The conduction band minimum (CBM) derives from the antibonding orbitals of O-H bonds, and is at variance much more extended. Experimentally determined positions of these band edge states have yet to reach a consensus. Early ultraviolet (UV) photoemission experiments by Delahay and collaborators reported photoemission threshold energies of 9.3 [3] and 10.06 eV [4]. More recent work by Winter et al. employed the liquid microjet technique and found a threshold energy of 9.9 eV [5]. For the unoccupied states, inverse photoemission and photoionization measurements placed the CBM at −1.2 eV with respect to the vacuum level [6,7]. This value was later revised to −0.74 eV, in light of the observation that excess electrons in liquid water could be initially captured in a localized trap state below the actual CBM [8]. Altogether, these measurements allude to a band gap of 8.7 eV, but associated with a sizable uncertainty of AE0.6 eV.To shed light on the electronic structure of water, it is necessary to resort to a fully ab initio method, which avoids the use of experimental input. Ab initio molecular dynamics (MD) simulations based on Kohn-Sham density-functional theory (DFT) have been extensively carried out to understand the structural and dynamical properties of water and of aqueous solutions. It is well recognized that the use of semilocal density functionals precludes a faithful description of the electronic structure and the predicted band gap of liquid water is apparently too small [9,10]. Hybrid functionals improve the description of the electronic structure [10], but the mixing parameter of the Fock exchange is not known a priori without the input from experiment ...

Cartilage development and homeostasis are influenced by miR-320, which directly targets MMP-13 and regulates chondrogenesis and the IL-1β-stimulated catabolic effect in mouse chondrocytes.

Accurate determination of band gaps of extended systems remains challenging within the framework of GW. Notably, the quasiparticle self-consistent GW systematically overestimates the band gaps as a result of the neglect of vertex corrections in the screening. Here we propose the use of an efficient bootstrap exchange-correlation kernel to account for the vertex corrections in self-consistent GW calculations. The approximate kernel leads to accurate band gaps for various extended systems, including simple sp semiconductors, wide band-gap insulators, and 3d transition-metal compounds. The accuracy is compatible with that obtained via the solution of the Bethe-Salpeter equation, making the method particularly useful for band-gap predictions of large-scale systems.