Shape effect on the valley splitting in lead selenide nanowires

Abstract

We study the cross-section shape and size effects on the valley splitting in PbSe nanowires within the framework of empirical sp 3 d 5 s * tight-binding method. We consider ideallized prismatic nanowires, grown along [110], with the cross-section shape varying from rectangular (terminated by {001} and {110} facets) to rhombic (terminated mostly by {111} facets). The valley splitting energies have the maximal value (up to hundreds meV) in rectangular nanowires, while in rhombic ones they are almost absent. The shape dependence is shown to be similar for a wide range cross-section sizes and different point symmetries of nanowires. arXiv:1901.09773v1 [cond-mat.mes-hall]

Enhanced Valley Splitting of Exciton Emission in Colloidal PbSe Quantum Dots When the Interdot Distance Coincides with Onset of Förster Resonance Energy Transfer

“…As a result, the energy separation between the two bands increased from 38 to 73 meV when L decreased from 42 to 8 nm, as shown in Figure c. According to previous studies, the magnitude of the valley splitting ( i.e ., energy separation of the two bands) of PbSe QDs is intrinsically determined by the size and shape of QDs and nanorods. − Also, the energy separation of 38 meV before the appearance of FRET agrees well with the L-valley splitting of ∼30 meV previously reported for PbSe QDs with a diameter of 5.2 nm, strongly supporting the current assignment of splitting. However, in the present study the energy separation increased with decreasing L without changing the size and shape of the QDs.…”