title: Size-Dependent Structure Relations between Nanotubes and Encapsulated Nanocrystals.
abstract: The structural organization of compounds in a confined space of nanometer-scale cavities is of fundamental importance for understanding the basic principles for atomic structure design at the nanolevel. Here, we explore size-dependent structure relations between one-dimensional PbTe nanocrystals and carbon nanotube containers in the diameter range of 2.0-1.25 nm using high-resolution transmission electron microscopy and ab initio calculations. Upon decrease of the confining volume, one-dimensional crystals reveal gradual thinning, with the structure being cut from the bulk in either a <110> or a <100> growth direction until a certain limit of ∼1.3 nm. This corresponds to the situation when a stoichiometric (uncharged) crystal does not fit into the cavity dimensions. As a result of the in-tube charge compensation, one-dimensional superstructures with nanometer-scale atomic density modulations are formed by a periodic addition of peripheral extra atoms to the main motif. Structural changes in the crystallographic configuration of the composites entail the redistribution of charge density on single-walled carbon nanotube walls and the possible appearance of the electron density wave. The variation of the potential attains 0.4 eV, corresponding to charge density fluctuations of 0.14 e/atom.
authors.forename: Andrei A
authors.initials: AA
authors.lastname: Eliseev
authors.forename: Nikolay S
authors.identifier: 0000-0002-9398-5261
authors.initials: NS
authors.lastname: Falaleev
authors.affiliation: University of Vienna , 1090 Vienna, Austria.
authors.forename: Nikolay I
authors.identifier: 0000-0002-6459-2493
authors.initials: NI
authors.lastname: Verbitskiy
authors.affiliation: Kurnakov Institute of General and Inorganic Chemistry RAS , 119991 Moscow, Russia.
authors.forename: Andrei A
authors.initials: AA
authors.lastname: Volykhov
authors.forename: Lada V
authors.initials: LV
authors.lastname: Yashina
authors.affiliation: Shubnikov Institute of Crystallography RAS , 119333 Moscow, Russia.|NRC Kurchatov Institute , 123182 Moscow, Russia.
authors.forename: Andrei S
authors.initials: AS
authors.lastname: Kumskov
authors.affiliation: Shubnikov Institute of Crystallography RAS , 119333 Moscow, Russia.
authors.forename: Victoria G
authors.initials: VG
authors.lastname: Zhigalina
authors.affiliation: NRC Kurchatov Institute , 123182 Moscow, Russia.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Vasiliev
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Lukashin
authors.affiliation: Department of Physics, University of Warwick , Coventry, Warwickshire CV47AL, U.K.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sloan
authors.affiliation: Shubnikov Institute of Crystallography RAS , 119333 Moscow, Russia.
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Kiselev
keywords: 1D crystals; HRTEM; PbTe; Single-walled carbon nanotubes; atomic structure; confinement