Transformation of the electrical transport from the Efros and Shklovskii J. Phys. C 8, L49 1975 variable range hopping to the “hard gap” resistance was experimentally observed in a low temperature range as the Fe compositions in Zn1−xFexO1−v ferromagnetic semiconductor films increase. A universal form of the resistance versus temperature, i.e., exp TH /T+ TES/T 1/2 , was theoretically establish...

We introduce various exchange interactions in a model Hamiltonian for Ce3+ ions in cubic symmetry with three configurations (f0,f1,f2). With the impurity pseudo spin SI = 1/2, our Hamiltonian includes: (i) One-channel Sc = 1/2 Anderson model; (ii) Two-channel Sc = 1/2 Anderson model; (iii) An unforseen one-channel Sc = 3/2 Anderson model with a non-trivial fixed point; (iv) Mixing exchange inte...

Self-interaction corrected density functional theory was used to determine the self-interaction error for dissociating one-electron bonds. The self-interaction error of the unpaired electron mimics nondynamic correlation effects that have no physical basis where these effects increase for increasing separation distance. For short distances the magnitude of the self-interaction error takes a min...

The exchange interaction, J, between two spin centres is a convenient measure of through bond electronic communication. Here, we investigate quantum interference phenomena in a bis-copper six-porphyrin nanoring by electron paramagnetic resonance spectroscopy via measurement of the exchange coupling between the copper centres. Using an analytical expression accounting for both dipolar and exchan...

Spin accumulation is a crucial but imprecise concept in spintronics. In metal-based spintronics it is characterized in terms of semiclassical distribution functions. In semiconductors with a strong spin-orbit coupling the spin accumulation is interpreted as a superposition of coherent eigenstates. Both views can be reconciled by taking into account the electron-electron interaction: a sufficien...

We propose the local density approximation (LDA) plus an on-site Coulomb self-interaction-like correction (SIC) potential for describing sp-hybridized bonds in semiconductors and insulators. We motivate the present LDA+USIC scheme by comparing the exact exchange (EXX) hole with the LDA exchange hole. The LDA+USIC method yields good band-gap energies Eg and dielectric constants ε(ω≈ 0) of Si, Ge...

The common density functionals for the exchange-correlation energy make serious self-interaction errors in the molecular dissociation limit when real or spurious noninteger electron numbers N are found on the dissociation products. An "M-electron self-interaction-free" functional for positive integer M is one that produces a realistic linear variation of total energy with N in the range of M-1<...

We have calculated the temperature dependence of the frictional drag between spatially separated quantum wells with parallel two-dimensional electron gases due to interlayer electron-electron interaction mediated by virtual exchange of acoustic phonons due to piezoelectric and deformation potential interaction. It is shown that the frictional drag is dominated by the piezoelectric coupling. Acc...

The exchange interaction in a singlet-triplet qubit defined by two-electron states the double-quantum-dot system ("two-electron qubit") typically varies monotonically with and thus carries no sweet spot. Here we study four-electron ("four-electron qubit"). We demonstrate, using configuration-interaction calculations, that energy as function of detuning can be non-monotonic, suggesting existence...