Giant valley-Zeeman coupling in the surface layer of an intercalated transition metal dichalcogenide.

Spin-valley locking is ubiquitous among transition metal dichalcogenides with local or global inversion asymmetry, in turn stabilizing properties such as Ising superconductivity, and opening routes towards 'valleytronics'. The underlying valley-spin splitting is set by spin-orbit coupling but can be tuned via the application of external magnetic fields or through proximity coupling. However, only modest changes have been realized to date. Here, we investigate the electronic structure of the V-intercalated transition metal dichalcogenide V1/3NbS2 using microscopic-area spatially resolved and angle-resolved photoemission spectroscopy. Our measurements and corresponding density functional theory calculations reveal that the bulk magnetic order induces a giant valley-selective Ising coupling exceeding 50 meV in the surface NbS2 layer, equivalent to application of a ~250 T magnetic field. This energy scale is of comparable magnitude to the intrinsic spin-orbit splittings, and indicates how coupling of local magnetic moments to itinerant states of a transition metal dichalcogenide monolayer provides a powerful route to controlling their valley-spin splittings.

Selective gas adsorption in microporous metal-organic frameworks incorporating urotropine basic sites: an experimental and theoretical study.

The sorption of CO, CO2 and C2H2 by two urotropine-containing porous metal-organic framework materials [Zn4(dmf)(ur)2(ndc)4] (H2ndc = 2,6-naphthalenedicarboxylic acid; ur = urotropine; dmf = dimethylformamide) and [Zn11(H2O)2(ur)4(bpdc)11] (H4bpdc = 4,4'-biphenyldicarboxylic acid) incorporating free N-donors has been investigated. These materials show pronounced affinity for CO2 and C2H2, and these observations are supported by interaction energy and ab initio DFT calculations.

Ultra-stable nanoparticles in A(II)B(VI), (A(II) = Cd, Zn; BVI, = S, Se, Te) compounds.

Laser ablation on binary A(II)B(VI) compounds exhibits in time-of-flight mass spectra abundant peaks at stoichiometric (A(II)B(VI)),n with n = 13, 19, 33 and 34 measured on bulk powders of CdSe, CdS, CdTe, ZnS and ZnSe. Investigation on solution grown nanometer size particles of CdSe shown an existence of ultra-stable stoichiometric clusters (CdSe)13, (CdSe)19, (CdSe)33, (CdSe)34 and (CdSe)48. This set of n has not been predicted as particularly stable particles in previous bulk fragment models based on either zinc-blende or wurtzite, and a different type of structures is required to explain our experimental results. Present investigation shows that nanoparticles formed in vacuum as magic numbers above are found in solution as preferentially grown species in CdSe, and possibly in other A(II)B(VI). It is suggested that the high stability of the observed magic clusters originates from their specific structure as endohedral binary fullerenes, supposedly. These molecular-like particles composed of few tens of atoms lie between atom and solid, and exhibit novel materials functions not realizable in the bulk.

Crystal-like low frequency phonons in the low-density amorphous and high-density amorphous ices.

The structure and vibrational properties of high- and low-density amorphous (HDA and LDA, respectively) ices have been determined using reverse Monte Carlo, molecular dynamics, and lattice dynamics simulations. This combined approach leads to a more accurate and detailed structural description of HDA and LDA ices when compared to experiment than was previously possible. The water molecules in these ices form well connected hydrogen-bond networks that exhibit modes of vibration that extend throughout the solid and can involve up to 70% of all molecules. However, the networks display significant differences in their dynamical behavior. In HDA, the extended low-frequency vibrational modes occur in dense parallel two dimensional layers of water that are approximately 10 nm thick. In contrast, the extended modes in LDA resemble a holey structure that encapsulates many small pockets of nonparticipating water molecules.

Gate-induced switching and negative differential resistance in a single-molecule transistor: emergence of fixed and shifting states with molecular length.

The quantum transport of a gated polythiophene nanodevice is analyzed using density functional theory and nonequilibrium Green's function approach. For this typical molecular field effect transistor, we prove the existence of two main features of electronic components, i.e., negative differential resistance and good switching. Ab initio based explanations of these features are provided by distinguishing fixed and shifting conducting states, which are shown to arise from the interface and functional molecule, respectively. The results show that proper functional molecules can be used in conjunction with metallic electrodes to achieve basic electronics functionality at molecular length scales.