The two-dimensional structure of graphene, consisting of an isotropic hexagonal lattice of carbon atoms, shows fascinating electronic properties, such as a gapless energy band and Dirac fermion behavior of electrons at fermi surface. Anisotropy can be induced in this structure by electrochemical pressure. In this article, by using tight-binding method, we review anisotropy effects in the elect...

In this study the chemical properties of B6C4Si and C16 Clusters connected vitamin C have been investigated using density functional theory (DFT). NMR parameters and HOMO- LUMO Gap energy are calculated by using density functional method (B3LYP) with 6-311G* basis set. Calculations show that HOMO- LUMO Gap energy of vitamin C decreases after connecting to B6C4Si or C16 cluster decreasing of HOM...

We present numerical results for the magnetic susceptibility of a Heisenberg antiferromagnetic spin ladder, as a function of temperature and the spin-spin interaction strengths J ⊥ and J ||. These are contrasted with new bulk limit results for the dimer chain. A fit to the experimental susceptibility of the candidate spin-ladder compound vanadyl pyrophosphate, (VO) 2 P 2 O 7 , gives the paramet...

When a quantum-chaotic normal conductor is coupled to a superconductor, the random-matrix theory (RMT) predicts that a gap opens up in the excitation spectrum which is of universal size E(g)(RMT) approximately 0.3 Planck/t(D), where t(D) is the mean scattering time between Andreev reflections. We show that a scarred state of long lifetime t(S)>>t(D) suppresses the excitation gap over a window D...

We extend the density matrix renormalization group method to exploit Parity, C2 (rotation by π) and electron-hole symmtries of model Hamiltonians. We demonstrate the power of this method by obtaining the lowest energy states in all the eight symmetry subspaces of Hubbard chains with upto 50 sites. The ground-state energy, optical gap and spin gap of regular U = 4t and U = 6t Hubbard chains agre...

We observed highly efficient generation of electron-hole pairs due to impact excitation in single-walled carbon nanotube p-n junction photodiodes. Optical excitation into the second electronic subband E22 leads to striking photocurrent steps in the device I-V(SD) characteristics that occur at voltage intervals of the band-gap energy E(GAP)/e. Spatially and spectrally resolved photocurrent combi...

the monitoring and controlling of environmental pollutions are very important in biological and industrial processes, and a great interest is growing with the development of suitable gas–sensitive materials and hazardous chemical removal devices. in this work, the highly parameterized, empirical exchange–correlation functional m06–2x were employed to investigate the electronic sensitivity of pe...

The possibility of distinguishing between two higgs production mechanisms, W fusion and gluon fusion, due to rapidity gap existence is investigated using the Monte Carlo event generator PYTHIA. It is shown that, considering the designed CM energy and luminosity for the LHC, it is not possible to distinguish between the two higgs production processes as, for a given integrated luminosity, they l...

We explore generic ground-state and low-energy statistical properties of many-body bosonic and fermionic oneand two-body random ensembles (TBRE) in the dense limit, and contrast them with Random Matrix Theory (RMT). Weak differences in distribution tails can be attributed to the regularity or chaoticity of the corresponding Hamiltonians rather than the particle statistics. We finally show the u...