Modern Physics Letters B

The electronic behavior of semiconducting carbon nanotubes based CNTFET under the influence of radial deformation defect present in the channel is theoretically investigated using nonequilibrium Green's function method self-consistently coupled with three-dimensional electrostatics. It was found that deformation in the CNTFET channel composed of a small diameter semiconducting carbon nanotube can increase its conductance by a factor of 4 or more depending upon the average reduction in the C–C bond length after compression. This increase in CNTFET conductance is directly related to the movement of the electronic states toward the Fermi level when the tubes are squeezed. Furthermore, the device ON–OFF current ratio also decreases with increase in applied compression which makes it hard to switch-OFF the device.

Using first-principles calculations, we systematically investigate the defect physics in topological insulator AuTlS₂. An optimal growth condition is explicitly proposed to guide for the experimental synthesis. The stabilities of various native point defects under different growth conditions and different carrier environments are studied in detail. We show that the p-type conductivity is strongly preferred in AuTlS₂, and the band gap can be engineered by the control of intrinsic defects. Our results demonstrate that AuTlS₂ is an ideal p-type topological insulator which can be easily integrated with traditional semiconductor.

In this paper, we calculate the Laplacian spectra of a 3-prism graph and apply them. This graph is both planar and polyhedral, and belongs to the generalized Petersen graph. Using the regular structures of this graph, we obtain the recurrent relationships for Laplacian matrix between this graph and its initial state — a triangle — and further derive the corresponding relationships for Laplacian eigenvalues between them. By these relationships, we obtain the analytical expressions for the product and the sum of the reciprocals of all nonzero Laplacian eigenvalues. Finally we apply these expressions to calculate the number of spanning trees and mean first-passage time (MFPT) and see that the scaling of MFPT with the network size N is N², which is larger than those performed on some uniformly recursive trees.

In this paper, the thermodynamic properties of the superconducting state in the metallic hydrogen under the pressure at 347 GPa have been determined. In the framework of the Eliashberg formalism, it has been shown that the characteristic thermodynamic parameters deviate from the predictions of the BCS theory. In particular, the ratio ΔC(T_C)/C^N(T_C) decreases from 1.96 to 1.72 depending on the assumed value of the Coulomb pseudopotential (μ* ∈ 〈0.08, 0.15〉). On the other hand, the ratio increases from 0.150 to 0.158.

In this paper, we investigate the trade-off problem between the high robustness against cascading failures and the low costs of network constructions in complex networks. Since the important nodes with highly connected components usually play a key role in the network structure and network dynamics, we propose an optimal capacity allocation model based on node importance. The novel model will increase the capacities of those important nodes but reduce the network construction cost with the appropriate capacity allocation parameter. Moreover, we also discover that our matching model can enhance the robustness against cascading failures on the IEEE 300 network.

In this paper, an experimental verification of the relationship between the deformed Minkowsky space-time and the piezonuclear emission has been obtained by testing several cylindrical steel bars cyclically loaded in a mechanical fatigue machine. During the compression cycles, α-particles have been both detected by a ZnS(Ag) scintillator and a Geiger counter. Taking into account the theory of the deformed special relativity, we report that the emission only occurs after a specific value of energy is overcome. This value is strictly related to the weak and strong nuclear interactions, which in turn define the regions of Minkowsky and non-Minkowsky space-time.

In this paper, we propose a theoretical model to calculate the ground-state energy of light-hole exciton and its density of states in a microtube. This heterostructure has been fabricated and studied experimentally, and contains a double quantum well of AlGaAs/GaAs and large radius of curvature. The exciton trial function is taken as a product of the ground state wave functions of both the unbound electron and hole in the heterostructure, with an arbitrary correlation function that depends only on electron–hole separation. A renormalized Schrödinger equation for the correlation function is derived and coincides with the corresponding equation for a hydrogen atom in an effective isotropic and nonhomogeneous space. The binding energy of the ground state for an exciton in this heterostructure is calculated by the variational model proposed. The contribution to the energy given by the sublevels and the density of states is determined as a function of the width of the well and the aluminum concentration. The obtained results show good agreement with recent experimental observations.

In this paper, we investigate different decoherence sources with a charge qubit in a semiconductor quantum dot device. We distinguish between the intrinsic qubit population leakage and extrinsic environment noise, through a crucial difference in their signatures on the dynamics of the qubit. The results demonstrated here could help to develop unified understanding of decoherence mechanism in quantum dots and allow us to design suitable protocols for control and measurement.

In this paper, a scheme is presented for generation of W-type entangled states for n atoms trapped in separated cavities connected by optical fibers. The scheme only requires a single atom–cavity–fiber interaction and no classical field is needed. Due to these features, the scheme is simpler and more robust against decoherence than the previous ones. The scheme can also be used to realize quantum state transfer and controlled phase gates between qubits located at distant nodes of a quantum network.

In this paper, the resonant transmission of a moving particle which interacts with a one-dimensional array of N δ-function potentials is investigated. A suitable transfer matrix formulation is used to obtain the particle transmission. We give the parameters for perfect tunneling and the transcendental equation for the quasi-bound state energies for N = 2, 3 and 4. Conditions for perfect tunneling and resonant transmission are discussed for arrays with arbitrary N. A model to explain how the tunneling energy filter works in these systems is proposed here.