Interpretation of some Yb-based valence-fluctuating crystals as approximants to a dodecagonal quasicrystal. Issue 22 (3rd August 2018)

• Record Type: Journal Article
• Authors: Ishimasa, Tsutomu; Mihalkovič, Marek; Deguchi, Kazuhiko; Sato, Noriaki K.; de Boissieu, Marc
• Is Part Of: Philosophical magazine. Volume 98:Issue 22(2018)
• Page Start: 2018
• Page End: 2034
• Publication Date: 2018-08-03
• Subjects: Approximant -- quasicrystal -- dodecagonal -- valence-fluctuation -- Yb-based; Condensed matter -- Periodicals; Physics -- Periodicals; Matière condensée -- Périodiques; Physique -- Périodiques; 530.41
• DOI: 10.1080/14786435.2018.1470339
• Languages: English
• ISSNs: 1478-6435

Abstract

Abstract: The hexagonal ZrNiAl-type (space group: P 2 m ) and the tetragonal Mo2 FeB2 -type (space group: P 4 /mbm ) structures, which are formed in the same Yb-based alloys and exhibit physical properties related to valence-fluctuation, can be regarded as approximants of a hypothetical dodecagonal quasicrystal. Using Pd–Sn–Yb system as an example, a model of quasicrystal structure has been constructed, of which five-dimensional crystal (space group: P 12/ mmm, a DD = 5.66 Å and c = 3.72 Å) consists of four types of acceptance regions located at the following crystallographic sites; Yb [0 0 0 0 0], Pd[1/3 0 1/3 0 1/2], Pd[1/3 1/3 1/3 1/3 0] and Sn[1/2 00 1/2 1/2]. In the three-dimensional space, the quasicrystal is composed of three types of columns, of which c -projections correspond to a square, an equilateral triangle and a three-fold hexagon. They are fragments of two known crystals, the hexagonal α-YbPdSn and the tetragonal Yb2 Pd2 Sn structures. The model of the hypothetical quasicrystal may be applicable as a platform to treat in a unified manner the heavy fermion properties in the two types of Yb-based crystals.