title: Structural Channels and Atomic-Cluster Insertion in CsxBi4Te6(1 ≤ x ≤ 1.25) As Observed by Aberration-Corrected Scanning Transmission Electron Microscopy.
abstract: Microstructural analyses based on aberration-corrected scanning transmission electron microscopy (STEM) observations demonstrate that low-dimensional CsxBi4Te6materials, known to be a novel thermoelectric and superconducting system, contain notable structural channels that go directly along the b axis, which can be partially filled by atom clusters depending on the thermal treatment process. We successfully prepared two series of CsxBi4Te6single-crystalline samples using two different sintering processes. The CsxBi4Te6samples prepared using an air-quenching method show superconductivity at approximately 4 K, while the CsxBi4Te6with the same nominal compositions prepared by slowly cooling are nonsuperconductors. Moreover, atomic structural investigations of typical samples reveal that the structural channels are often empty in superconducting materials; thus, we can represent the superconducting phase as Cs1-yBi4Te6with considering the point defects in the Cs layers. In addition, the channels in the nonsuperconducting crystals are commonly partially occupied by triplet Bi clusters. Moreover, the average structures for these two phases are also different in their monoclinic angles (β), which are estimated to be 102.3° for superconductors and 100.5° for nonsuperconductors.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Ruixin
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Huaixin
authors.initials: H
authors.lastname: Yang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Guo
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Huanfang
authors.initials: H
authors.lastname: Tian
authors.affiliation: School of Science, Minzu University , Beijing 100081, China.
authors.forename: Honglong
authors.initials: H
authors.lastname: Shi
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter , Beijing 100190, China.
authors.forename: Genfu
authors.initials: G
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.|School of Physical Sciences, University of Chinese Academy of Sciences , Beijing 100049, China.|Collaborative Innovation Center of Quantum Matter , Beijing 100190, China.
authors.forename: Jianqi
authors.initials: J
authors.lastname: Li