T-shaped quantum wires in magnetic fields: Weakly confined magnetoexcitonsbeyond the diamagnetic limit

Bryant, GW Band, YB

Gw. Bryant et Yb. Band, T-shaped quantum wires in magnetic fields: Weakly confined magnetoexcitonsbeyond the diamagnetic limit, PHYS REV B, 6311(11), 2001, pp. 5304

37

INGLESE

Article

Apllied Physucs/Condensed Matter/Materiales Science

PHYSICAL REVIEW B

0163-1829 → ACNP

6311

11

2001

ISI

0163-1829(20010315)6311:11<5304:TQWIMF>2.0.ZU;2-B

Optical excitations of magnetoexcitons in T-shaped wires are calculated and compared with experiment. We find the single-particle states for electrons and holes confined to a wire in a magnetic field and use these states as a basis for calculations of magnetoexciton states. We accurately reproduce t he field dependence of the exciton states and explain the small, field-indu ced, energy shifts that are observed for these states. The shifts are small because the T-junction provides weak confinement, rather than strong quant um confinement. Diamagnetic shifts calculated from perturbation theory fail to describe the experimental results. We determine when perturbation theor y is valid for these nanostructures and which gauge should be used to give the diamagnetic shift that best reproduces the held dependence at low field s.