Insulator-to-metal transition in the black diamond from molecular-dynamics-Landauer method.

The critical condition and mechanism of the insulator-to-metal transition (IMT) for the black diamond were studied by the molecular-dynamics-Landauer method. The IMT will occur at sufficiently high contents of vacancies in the diamond. The critical concentration of vacancies for the IMT might be between V:C (0.

Recent progress in 2D bipolar magnetic semiconductors.

Bipolar magnetic semiconductor (BMS) is a class of magnetic semiconductors, whose valence band maximum and conduction band minimum are fully spin-polarized with opposite spin directions. Due to the special energy band, half-metallicity can be easily obtained in BMS by gate voltage, and the spin polarization can be reversed between spin-up and down when the gate voltage switches from positive to negative. BMSs have great potential applications in spintronic devices, such as the field-effect spin valves, spin filters and spin transistors,.

Boosting photodetection performance of CsAgBiBr through A-site Rb substitution and interfacial engineering.

Bismuth-based double perovskite CsAgBiBr shows promise as a photodetection material. However, its detection performance and application are limited by high-exciton binding energy and poor carrier mobility. In this study, we address these limitations by delicately designing a solution-based method for incorporating A-site Rubidium (Rb) substitution into CsAgBiBr double perovskite films.

Computational design of a reliable intermediate-band photovoltaic absorber based on diamond.

To reduce the wide bandgap of diamond and expand its applications in the photovoltaic fields, a diamond-based intermediate-band (IB) material C-Ge-V alloy was designed by first-principles calculations. By replacing some C with Ge and V in the diamond, the wide bandgap of the diamond can be reduced sharply and a reliable IB, which is mainly formed by the d states of V, can be formed in the bandgap. With the increase of Ge content, the total bandgap of the C-Ge-V alloy will be reduced and close to the optimal value of an IB material.

Ferroelectric control of band alignments and magnetic properties in the two-dimensional multiferroic VSe/InSe.

Our first-principles evidence shows that the two-dimensional (2D) multiferroic VSe/InSeexperiences continuous change of electronic structures, i.e. with the change of the ferroelectric (FE) polarization of InSe, the heterostructure can possess type-I, -II, and -III band alignments.

VSnanosheet as a promising candidate of recycle and reuse NOgas sensor and capturer: a DFT study.

We describe the utilization of VSnanosheet as high sensing response, reuse, and thermodynamic stability at room temperature NOand NO gas sensors by using the density functional theory method. We focus on the electronic structures and adsorption energy toward a variety of gaseous molecules (such as O, CO, HO, NH, NO, and NO) adsorbed on the VSnanosheet. The results show that chemical interactions existed between NO/NOmolecules and VSnanosheet due to sizable adsorption energy and strong covalent (S-N) bonds.

Electric control of nearly free electron states and ferromagnetism in the transition-metal dichalcogenides monolayers.

Using the first-principles calculations, we explore the nearly free electron (NFE) states in the transition-metal dichalcogenides(= Mo, W;= S, Se, Te) monolayers. It is found that both the external electric field and electron (not hole) injection can flexibly tune the energy levels of the NFE states, which can shift down to the Fermi level and result in novel transport properties. In addition, we find that the valley polarization can be induced by both electron and hole doping in MoTemonolayer due to the ferromagnetism induced by the charge injection, which, however, is not observed in other five kinds ofmonolayers.

Deep-level impurities hyperdoped diamond: a first-principles calculations.

A hyperdoped diamond material is engineered by first-principles calculations in this work. Several deep-level elements, such as S, Se, Te, Co, Au, V, Ni, are chosen as dopants in the diamond. The formation energy results show that the substitutional configuration of the dopants is more stable than the interstitial ones.

Precise Phase Control of Large-Scale Inorganic Perovskites via Vapor-Phase Anion-Exchange Strategy.

Anion exchange offers great flexibility and high precision in phase control, compositional engineering, and optoelectronic property tuning. Different from previous successful anion exchange process in liquid solution, herein, a vapor-phase anion-exchange strategy is developed to realize the precise phase and bandgap control of large-scale inorganic perovskites by using gas injection cycle, producing some perovskites such as CsPbCl which has never been reported in thin film morphology. Ab initio calculations also provide the insightful mechanism to understand the impact of anion exchange on tuning the electronic properties and optimizing the structural stability.

Silicene/boron nitride heterostructure for the design of highly efficient anode materials in lithium-ion battery.

The performance of silicene/boron nitride heterostructure as anode material in lithium-ion batteries (LIBs) has been investigated by first-principles calculations. From the interfacial synergy effect, an enhanced adsorption of Li ions on BN is found in the resulted heterostructure compared with pristine BN system. Also, lowered diffusion barriers are found in the BN/Li/silicene and BN/silicene/Li systems compared with pristine silicene system.

MoB: a new multifunctional transition metal diboride monolayer.

Several layered transition metal borides can now be realized by a simple and general fabrication method (Fokwa et al 2018 Adv. Mater. 30 1704181), inspiring our interest to transition metal borides monolayer.

Br doped porous bismuth oxychloride micro-sheets with rich oxygen vacancies and dominating {0 0 1} facets for enhanced nitrogen photo-fixation performances.

Bismuth oxychloride micro-sheets with rich oxygen vacancies (BiOCl-OV) are firstly prepared through a surfactant assisted solvothermal method. Due to the selective surfactant adsorption, the as-prepared BiOCl-OV exposes high percentage {0 0 1} facets. Moreover, the ion-exchange process not only introduces Br atoms but also creates cavities in crystal structure of the Br doped BiOCl-OV (Br-BiOCl-OV).

Modulation of the electronic properties and spin polarization of 2H VS nanoribbons by tuning ribbon widths and edge decoration.

The band structures and spin-polarization characteristics of armchair and zigzag VS2 nanoribbons with different terminated edges are investigated based on density functional theory (DFT) calculations with a spin polarized meta-GGA. The results reveal that zigzag 2H VS2 nanoribbons exhibit metal, half-metal, or semiconductor electrical characteristics with different edge decorations or ribbon widths. And the spin polarized ratio can achieve 100% self-polarization for the zigzag VS2 nanoribbons with V atom edges.

Multifunctional 2D CuSe monolayer nanodevice.

In a very recent experimental work (Gao et al 2018 Adv. Mater. 30 1707055), a graphene-like CuSe monolayer (ML) was realized.

Negative differential conductance effect and electrical anisotropy of 2D ZrB monolayers.

Two-dimensional (2D) metal-diboride ZrB monolayers was predicted theoretically as a stable new electronic material (Lopez-Bezanilla 2018 Phys. Rev. Mater.

How does the electric current propagate through fully-hydrogenated borophene?

We study the electronic transport properties of two-dimensional (2D) fully-hydrogenated borophene (namely, borophane), using density functional theory and non-equilibrium Green's function approaches. Borophane shows a perfect electrical transport anisotropy and is promising for applications. Along the peak- or equivalently the valley-parallel direction, 2D borophane exhibits a metallic characteristic and its current-voltage (I-V) curve shows a linear behavior, corresponding to the ON state in borophane-based nano-switches.

The electronic transport properties of zigzag phosphorene-like MX (M = Ge/Sn, X = S/Se) nanostructures.

Single-layer phosphorene-like MX sheets have aroused new interest and could become a family of nanomaterials in physics and materials science. Using a first-principles method combined with non-equilibrium Green's function (NEGF) theory, we study the electronic transport properties of the zigzag phosphorene-like MX (M = Ge/Sn, X = S/Se) nanostructures. The results demonstrate that GeS and GeSe nanoribbons display very similar electronic transport properties.

A theoretical simulation of small-molecules sensing on an S-vacancy SnS monolayer.

Using first-principle atomistic simulations, we focused on the electronic structures of small gas molecules (CO, HO, NH, NO, and NO) adsorbed on the S-vacancy SnS monolayer. The results show that HO and CO molecules were physisorbed on the S-vacancy SnS monolayer, whereas NH, NO, and NO molecules were chemisorbed on the S-vacancy SnS monolayer via strong covalent bonds. Moreover, our calculations show that HO and NH act as charge donors, whereas CO, NO, and NO gas molecules act as acceptors.

The rectifying and negative differential resistance effects in graphene/h-BN nanoribbon heterojunctions.

We investigate the electronic transport properties of four types of lateral graphene/h-BN nanoribbon heterojunctions using the non-equilibrium Green's function method in combination with the density functional theory. The results show that the heterojunction displays an interesting rectifying effect when the interface has a left-right type structure, while a pronounced negative differential resistance (NDR) effect when the interface has an up-down type structure. Moreover, when the interface of the heterojunction has a left-bank or right-bank type structure, it presents the rectifying (with a larger rectification ratio) and NDR effects.

The magnetism and spin-dependent electronic transport properties of boron nitride atomic chains.

Very recently, boron nitride atomic chains were successively prepared and observed in experiments [O. Cretu et al., ACS Nano 8, 11950 (2015)].

Electronic transport properties of the first all-boron fullerene B40 and its metallofullerene Sr@B40.

The newly-discovered B40 is the first experimentally observed all-boron fullerene and has potential applications in molecular devices. Herein, we report the electronic transport properties of B40 and its metallofullerene, Sr@B40, using the first-principles technique. We obtain the conductance of B40 fullerene, which is about 130 μS and can be increased by embedding a strontium metal atom in the cage due to the decreased energy gap.

Spin-dependent thermoelectronic transport of a single molecule magnet Mn(dmit)2.

We investigate spin-dependent thermoelectronic transport properties of a single molecule magnet Mn(dmit)2 sandwiched between two Au electrodes using first-principles density functional theory combined with nonequilibrium Green's function method. By applying a temperature difference between the two Au electrodes, spin-up and spin-down currents flowing in opposite directions can be induced due to asymmetric distribution of the spin-up and spin-down transmission spectra around the Fermi level. A pure spin current and 100% spin polarization are achieved by tuning back-gate voltage to the system.

Improving electronic transport of zigzag graphene nanoribbons by ordered doping of B or N atoms.

Using an ab initio method, we explored electronic structures and transport properties of zigzag graphene nanoribbons (ZGNRs) with ordered doping of B or N atoms. We find B or N atoms doping can increase significantly the conductance of the ZGNRs with an even number of zigzag chains due to additional conducting channels being induced and the breakdown of parity limitation. The higher the doping concentration, the larger the current amplification factor obtained.

High-efficiency switching effect in porphyrin-ethyne-benzene conjugates.

We have explored the electronic transport properties of porphyrin-ethyne-benzene conjugates using an ab initio method. The results indicate that these ethyne-bridged phenyl porphyrin molecules can be used as candidates for molecular switching devices. The coplanar conformation of phenyl and porphyrin moieties allows a far larger current than the perpendicular conformation due to the near vanishing overlap of the frontier molecular orbitals (π channels) in the porphyrin and phenyl parts in the latter.

Theoretical characteristics of the bound states of M-X complexes (M = Cu, Ag, and Au, and X = He, Ne, and Ar).

The potential energy curves (PECs) of the bound states of M-X (M=Cu, Ag, and Au and X=He, Ne, and Ar) complexes have been calculated using the coupled cluster singles and doubles method with perturbative treatment of triple excitations. Large basis sets and bond functions, as well as the basis set superposition errors, are employed to obtain accurate PECs. The analytical potential energy functions (APEFs) are fitted using the PECs.