Amita Wadehra

Magnetic states and optical properties of single-layer carbon-doped hexagonal boron nitride

We show that carbon-doped hexagonal boron nitride (h-BN) has extraordinary properties with many possible applications. We demonstrate that the substitution-induced impurity states, associated with carbon atoms, and their interactions dictate the electronic structure and properties of C-doped h-BN. Furthermore, we show that stacking of localized impurity states in small C clusters embedded in h-BN forms a set of discrete energy levels in the wide gap of h-BN. The electronic structures of these C clusters have a plethora of applications in optics, magneto-optics, and opto-electronics.

Band offsets of semiconductor heterostructures: A hybrid density functional study

We demonstrate the accuracy of the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional for computing the band offsets of semiconductor alloy heterostructures. The highlight of this study is the computation of conduction band offsets with a reliability that has eluded standard density functional theory. A special quasirandom structure models an infinite random pseudobinary alloy for constructing heterostructures along the (001) growth direction. Our results for a variety of heterostructures establish HSE06’s relevance to band engineering of high-performance electrical and optoelectronic devices.

Magnetic properties of Fe chains on Cu2N/Cu(100): A density functional theory study

We present a density functional study of the magnetic properties of Fe adatoms on Cu2N/Cu(100) surface. The magnetic anisotropy energies of a single Fe atom are in excellent agreement with the available experiments. Our results for the spin densities and exchange coupling strengths for Fe dimer and trimer establish antiferromagnetic configuration to be the ground state due to predominant superexchange interaction mediated by nitrogen atoms in this system.