Atomic transition region at the crossover between quantum dots to molecules

Bruno Ullrich, A. Antillón, Mithun Bhowmick, J. S. Wang, Haowen Xi

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The presented investigations aim to pinpoint the crossover of lead sulfide (PbS) quantum dots (QDs) with a shrinking diameter to a molecular state. We have measured the transmittance of strongly confined PbS QDs of 2.7, 3.1, 4.7 and 4.8 nm size in the temperature range of 10-300 K. Fitting these results with the classical Fan theory revealed that the average phonon energy coincides with the reduction of the QD diameters, pointing to a limitation of coherent atom movements in strongly confined matter. The phonons vanish at QDs limited to 90 atoms corresponding to a size of 1.7 nm, which we define as the critical size for the solid-to-molecule crossover. The result is confirmed by a calculation based on the uncertainty principle.

Original languageEnglish
Article number025801
JournalPhysica Scripta
Volume89
Issue number2
DOIs
Publication statusPublished - Feb 2014
Externally publishedYes

Fingerprint

Quantum Dots
Crossover
crossovers
quantum dots
Molecules
molecules
lead sulfides
Uncertainty Principle
Phonons
Transmittance
Shrinking
Phonon
fans
atoms
Vanish
transmittance
phonons
Energy
Range of data
temperature

Keywords

  • optical properties of quantum dots
  • PbS quantum dots
  • phase transition
  • phonons in quantum dots
  • quantum dot preparation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Atomic and Molecular Physics, and Optics
  • Mathematical Physics

Cite this

Ullrich, B., Antillón, A., Bhowmick, M., Wang, J. S., & Xi, H. (2014). Atomic transition region at the crossover between quantum dots to molecules. Physica Scripta, 89(2), [025801]. https://doi.org/10.1088/0031-8949/89/02/025801

Atomic transition region at the crossover between quantum dots to molecules. / Ullrich, Bruno; Antillón, A.; Bhowmick, Mithun; Wang, J. S.; Xi, Haowen.

In: Physica Scripta, Vol. 89, No. 2, 025801, 02.2014.

Research output: Contribution to journalArticle

Ullrich, B, Antillón, A, Bhowmick, M, Wang, JS & Xi, H 2014, 'Atomic transition region at the crossover between quantum dots to molecules', Physica Scripta, vol. 89, no. 2, 025801. https://doi.org/10.1088/0031-8949/89/02/025801
Ullrich, Bruno ; Antillón, A. ; Bhowmick, Mithun ; Wang, J. S. ; Xi, Haowen. / Atomic transition region at the crossover between quantum dots to molecules. In: Physica Scripta. 2014 ; Vol. 89, No. 2.
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