| 1. |
- Nowakowska, Sylwia, et al.
(författare)
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Adsorbate-Induced Modification of the Confining Barriers in a Quantum Box Array
- 2018
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:1, s. 768-778
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Tidskriftsartikel (refereegranskat)abstract
- Quantum devices depend on addressable elements, which can be modified separately and in their mutual interaction. Self-assembly at surfaces, for example, formation of a porous (metal-) organic network, provides an ideal way to manufacture arrays of identical quantum boxes, arising in this case from the confinement of the electronic (Shockley) surface state within the pores. We show that the electronic quantum box state as well as the interbox coupling can be modified locally to a varying extent by a selective choice of adsorbates, here C60, interacting with the barrier. In view of the wealth of differently acting adsorbates, this approach allows for engineering quantum states in on-surface network architectures.
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| 2. |
- Ahsan, Aisha, et al.
(författare)
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Phase Transitions in Confinements: Controlling Solid to Fluid Transitions of Xenon Atoms in an On-Surface Network
- 2019
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Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- This study reports on "phase" transitions of Xe condensates in on-surface confinements induced by temperature changes and local probe excitation. The pores of a metal-organic network occupied with 1 up to 9 Xe atoms are investigated in their propensity to undergo "condensed solid" to "confined fluid" transitions. Different transition temperatures are identified, which depend on the number of Xe atoms in the condensate and relate to the stability of the Xe clustering in the condensed "phase." This work reveals the feature-rich behavior of transitions of confined planar condensates, which provide a showcase toward future "phase-transition" storage media patterned by self-assembly. This work is also of fundamental interest as it paves the way to real space investigations of reversible solid to fluid transitions of magic cluster condensates in an array of extremely well-defined quantum confinements.
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| 3. |
- Ahsan, Aisha, et al.
(författare)
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Watching nanostructure growth: kinetically controlled diffusion and condensation of Xe in a surface metal organic network
- 2019
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Ingår i: Nanoscale. - : ROYAL SOC CHEMISTRY. - 2040-3364 .- 2040-3372. ; 11:11, s. 4895-4903
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Tidskriftsartikel (refereegranskat)abstract
- Diffusion, nucleation and growth provide the fundamental access to control nanostructure growth. In this study, the temperature activated diffusion of Xe at and between different compartments of an on-surface metal organic coordination network on Cu(111) has been visualized in real space. Xe atoms adsorbed at lower energy sites become mobile with increased temperature and gradually populate energetically more favourable binding sites or remain in a delocalized fluid form confined to diffusion along a topological subset of the on-surface network. These diffusion pathways can be studied individually under kinetic control via the chosen thermal energy kT of the sample and are determined by the network and sample architecture. The spatial distribution of Xe in its different modes of mobility and the time scales of the motion is revealed by Scanning Tunneling Microscopy (STM) at variable temperatures up to 40 K and subsequent cooling to 4 K. The system provides insight into the diffusion of a van der Waals gas on a complex structured surface and its nucleation and coarsening/growth into larger condensates at elevated temperature under thermodynamic conditions.
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