Emergence of bound states in ballistic magnetotransport of graphene antidots

An experimental method for detection of bound states around an antidot formed from a hole in a graphene sheet is proposed by measuring the ballistic two terminal conductances. In particularly, we consider the effect of bound states formed by magnetic field on the two terminal conductance and show that one can observe Breit-Wigner like resonances in the conductance as a function of the Fermi level close to the energies of the bound states. In addition, we develop a new numerical method in which the computational effort is proportional to the linear dimensions, instead of the area of the scattering region beeing typical for the existing numerical recursive Green's function method.Comment: 7 pages, 6 figure

Lande-like formula for the g factors of hole-nanowire subband edges

We have analyzed theoretically the Zeeman splitting of hole-quantum-wire subband edges. As is typical for any bound state, their g factor depends on both an intrinsic g factor of the material and an additional contribution arising from a finite bound-state orbital angular momentum. We discuss the quantum-confinement-induced interplay between bulk-material and orbital effects, which is nontrivial due to the presence of strong spin-orbit coupling. A compact analytical formula is provided that elucidates this interplay and can be useful for predicting Zeeman splitting in generic hole-wire geometries.Comment: 4 pages, 2 figure

Additive trees in the analysis of community data

The paper advocates a more extensive use of additive trees in community ecology. When the distance/dissimilarity coefficient is selected carefully, these trees can illuminate structural aspects that are not obvious otherwise. In particular, starting from squared distances based on presence/absence data, the resulting trees approximate relationships in species richness, a feature not available through other graphical techniques. The construction of additive trees is illustrated by three actual examples, representing different circumstances in the analysis of grassland community data

A Halomethane thermochemical network from iPEPICO experiments and quantum chemical calculations

Internal energy selected halomethane cations CH3Cl+, CH2Cl2+, CHCl3+, CH3F+, CH2F2+, CHClF2+ and CBrClF2+ were prepared by vacuum ultraviolet photoionization, and their lowest energy dissociation channel studied using imaging photoelectron photoion coincidence spectroscopy (iPEPICO). This channel involves hydrogen atom loss for CH3F+, CH2F2+ and CH3Cl+, chlorine atom loss for CH2Cl2+, CHCl3+ and CHClF2+, and bromine atom loss for CBrClF2+. Accurate 0 K appearance energies, in conjunction with ab initio isodesmic and halogen exchange reaction energies, establish a thermochemical network, which is optimized to update and confirm the enthalpies of formation of the sample molecules and their dissociative photoionization products. The ground electronic states of CHCl3+, CHClF2+ and CBrClF2+ do not confirm to the deep well assumption, and the experimental breakdown curve deviates from the deep well model at low energies. Breakdown curve analysis of such shallow well systems supplies a satisfactorily succinct route to the adiabatic ionization energy of the parent molecule, particularly if the threshold photoelectron spectrum is not resolved and a purely computational route is unfeasible. The ionization energies have been found to be 11.47 ± 0.01 eV, 12.30 ± 0.02 eV and 11.23 ± 0.03 eV for CHCl3, CHClF2 and CBrClF2, respectively. The updated 0 K enthalpies of formation, ∆fHo0K(g) for the ions CH2F+, CHF2+, CHCl2+, CCl3+, CCl2F+ and CClF2+ have been derived to be 844.4 ± 2.1, 601.6 ± 2.7, 890.3 ± 2.2, 849.8 ± 3.2, 701.2 ± 3.3 and 552.2 ± 3.4 kJ mol–1, respectively. The ∆fHo0K(g) values for the neutrals CCl4, CBrClF2, CClF3, CCl2F2 and CCl3F and have been determined to be –94.0 ± 3.2, –446.6 ± 2.7, –702.1 ± 3.5, –487.8 ± 3.4 and –285.2 ± 3.2 kJ mol–1, respectively

Electrical control over single hole spins in nanowire quantum dots

Single electron spins in semiconductor quantum dots (QDs) are a versatile platform for quantum information processing, however controlling decoherence remains a considerable challenge. Recently, hole spins have emerged as a promising alternative. Holes in III-V semiconductors have unique properties, such as strong spin-orbit interaction and weak coupling to nuclear spins, and therefore have potential for enhanced spin control and longer coherence times. Weaker hyperfine interaction has already been reported in self-assembled quantum dots using quantum optics techniques. However, challenging fabrication has so far kept the promise of hole-spin-based electronic devices out of reach in conventional III-V heterostructures. Here, we report gate-tuneable hole quantum dots formed in InSb nanowires. Using these devices we demonstrate Pauli spin blockade and electrical control of single hole spins. The devices are fully tuneable between hole and electron QDs, enabling direct comparison between the hyperfine interaction strengths, g-factors and spin blockade anisotropies in the two regimes

Perspectivization and modes of quoting in Hungarian

This paper examines modes of quoting with special regard to the organization of perspective. Due to the pragmatic interest of the study, our focus is on the functioning of two context-dependent vantage points, the subject of consciousness and the referential centre. Our key question about the former is to whom speaking as a sign of active consciousness is attributed and how this is linguistically marked. As regards the latter, the central issue is from where and how the spatio-temporal and interpersonal relations of the quoted discourse are represented.Further problems to be discussed include the questions of how and to what extent quoting is associated with pragmatic or metapragmatic awareness, and how various quoting modes may differ along this dimension.Although the paper is mostly concerned with a ‘universal pragmatic’ characterization of the functioning of perspective in quotations, it also highlights some language-particular features of Hungarian quoting strategies and touches on their evolution in the history of the language

Correlation between age basal diameter of Fraxinus Ornus L. in three ecologically contrasting habitats

Manna ash (Fraxinus ornus L.) is a typical deciduous tree of South European distributioin reaching the northern border of its range in the Carpathian Basin. The correlation between age and basal diameter of this tree was analysed in three ecologically contrasting habitats, as follows. (1) Succesional habitat. Abandonedframland with scattered occurrence of manna ash as a colonisong tree of this area. (2) Austrian pine plantation, where manna ash often forms a spontaneous subordinate tree or shrub layer. (3) Cotino-Quercetum pubescentis, the naturla vegetation on south facing calcareous hillslopes in Hungary, where Quercus pubescenes Willd. and Fraxinus ornus codominate in the low canopy. At each sampling site 21 individuals were selected with an even distribution within circumference categories ranging  from 6cm to 60cm. Circumference measurements were made at the base of the trunk, or cores were taken by a driller. Linear regression analysis was applied to test the correlation between age and diameter