Exchange interactions and magnetic phases of transition metal oxides: benchmarking advanced ab initio methods

The magnetic properties of the transition metal monoxides MnO and NiO are investigated at equilibrium and under pressure via several advanced first-principles methods coupled with Heisenberg Hamiltonian MonteCarlo. The comparative first-principles analysis involves two promising beyond-local density functionals approaches, namely the hybrid density functional theory and the recently developed variational pseudo-self-interaction correction method, implemented with both plane-wave and atomic-orbital basis sets. The advanced functionals deliver a very satisfying rendition, curing the main drawbacks of the local functionals and improving over many other previous theoretical predictions. Furthermore, and most importantly, they convincingly demonstrate a degree of internal consistency, despite differences emerging due to methodological details (e.g. plane waves vs. atomic orbitals

A variational pseudo-self-interaction correction approach: ab-initio description of correlated oxides and molecules

We present a fully variational generalization of the pseudo self-interaction correction (VPSIC) approach previously presented in two implementations based on plane-waves and atomic orbital basis set, known as PSIC and ASIC, respectively. The new method is essentially equivalent to the previous version for what concern the electronic properties, but it can be exploited to calculate total-energy derived properties as well, such as forces and structural optimization. We apply the method to a variety of test cases including both non-magnetic and magnetic correlated oxides and molecules, showing a generally good accuracy in the description of both structural and electronic properties.Comment: 23 pages, 9 tables, 16 figure

Atomic self-interaction correction for molecules and solids

We present an atomic orbital based approximate scheme for self-interaction correction (SIC) to the local density approximation of density functional theory. The method, based on the idea of Filippetti and Spaldin [Phys. Rev. B 67, 125109 (2003)], is implemented in a code using localized numerical atomic orbital basis sets and is now suitable for both molecules and extended solids. After deriving the fundamental equations as a non-variational approximation of the self-consistent SIC theory, we present results for a wide range of molecules and insulators. In particular, we investigate the effect of re-scaling the self-interaction correction and we establish a link with the existing atomic-like corrective scheme LDA+U. We find that when no re-scaling is applied, i.e. when we consider the entire atomic correction, the Kohn-Sham HOMO eigenvalue is a rather good approximation to the experimental ionization potential for molecules. Similarly the HOMO eigenvalues of negatively charged molecules reproduce closely the molecular affinities. In contrast a re-scaling of about 50% is necessary to reproduce insulator bandgaps in solids, which otherwise are largely overestimated. The method therefore represents a Kohn-Sham based single-particle theory and offers good prospects for applications where the actual position of the Kohn-Sham eigenvalues is important, such as quantum transport.Comment: 16 pages, 7 figure

Exchange Interaction and TcT_c in Alkaline-earth-metal-oxide-based DMS without Magnetic Impurities: First Principle Pseudo-SIC and Monte Carlo Calculation

The prospects of half-metallic ferromagnetism being induced by the incorporation of C atoms into alkaline-earth-metal-oxides are investigated by the first principle calculation. The origin of the ferromagnetism is discussed through the calculation of the electronic structure and exchange coupling constant by using the pseudo-potential-like self-interaction-corrected local spin density method. The Curie temperature ($T_c$) is also predicted by employing the Monte Carlo simulation. It is shown that by taking the electron self-interaction into account, the half-metallic ferromagnetism induced by C in the host materials is more stabilized in comparison with the standard LDA case, and the C's $2p$ electron states in the bandgap become more localized resulting in the predominance of the short-ranged exchange interaction. While the ferromagnetism in MgO$_{1-x}$C$_x$ is stabilized due to the exchange interaction of the $1st$-nearest neighbor pairs and might be suppressed by the anti-ferromagnetic super-exchange interaction at higher $x$, the ferromagnetism in CaO$_{1-x}$C$_x$, SrO$_{1-x}$C$_x$, and BaO$_{1-x}$C$_x$ is stabilized by both the $1st$- and $2nd$-nearest neighbor pairs, and $T_c$ monotonously increases with the C concentration.Comment: 5 pages, 5 figure

Divergent clonal evolution of blastic plasmacytoid dendritic cell neoplasm and chronic myelomonocytic leukemia from a shared TET2-mutated origin

From Springer Nature via Jisc Publications RouterHistory: received 2020-11-25, rev-recd 2021-02-15, accepted 2021-03-11, registration 2021-03-12, pub-electronic 2021-04-08, online 2021-04-08, pub-print 2021-11Publication status: PublishedFunder: Oglesby Charitable TrustFunder: Pickering family donationFunder: Blood Cancer UK Clinician Scientist Fellowship (15030) Oglesby Charitable Trus

Potential therapeutic applications of microbial surface-activecompounds

Numerous investigations of microbial surface-active compounds or biosurfactants over the past two decades have led to the discovery of many interesting physicochemical and biological properties including antimicrobial, anti-biofilm and therapeutic among many other pharmaceutical and medical applications. Microbial control and inhibition strategies involving the use of antibiotics are becoming continually challenged due to the emergence of resistant strains mostly embedded within biofilm formations that are difficult to eradicate. Different aspects of antimicrobial and anti-biofilm control are becoming issues of increasing importance in clinical, hygiene, therapeutic and other applications. Biosurfactants research has resulted in increasing interest into their ability to inhibit microbial activity and disperse microbial biofilms in addition to being mostly nontoxic and stable at extremes conditions. Some biosurfactants are now in use in clinical, food and environmental fields, whilst others remain under investigation and development. The dispersal properties of biosurfactants have been shown to rival that of conventional inhibitory agents against bacterial, fungal and yeast biofilms as well as viral membrane structures. This presents them as potential candidates for future uses in new generations of antimicrobial agents or as adjuvants to other antibiotics and use as preservatives for microbial suppression and eradication strategies