Unusual physical properties ofKCu7−xS4at diffusive one-dimensional ordering transitions

On the Electrochemically Grown Quasi-One-Dimensional KCu7-xS4 Series (0 ⩽ x ⩽ 0.34): Nonstoichiometry, Superlattice, and Unusual Phase Transitions

“…Neither report has found vacancies that would give rise to nonstoichiometry on A-site cations. Through the electronic band structure calculations of KCu 7 - x S 4 and temperature-dependent studies of their resistance, thermal conductivity, thermoelectric power, and heat capacity ( C p ) properties, we have come to the same conclusion as Berger et al that the resistivity anomalies likely originate from the ordering of Cu + cations. Accordingly, we have proposed a diffusive one-dimensional ordering model concerning the vacancy ordering of the chain-site copper cations at transitions …”

“…In particular, we focus our attention on the room-temperature ordering patterns for the tetrahedral Cu + cations. We include some preliminary results from temperature-dependent magnetic susceptibility measurements and electron diffraction studies in an attempt to support our recently proposed diffusive one-dimensional ordering model . We also briefly discuss the correlation in structure and properties with the previously studied K 3 Cu 8 S 6 phase.…”

High Hole Mobility and Nonsaturating Giant Magnetoresistance in the New 2D Metal NaCu4Se4 Synthesized by a Unique Pathway

“…The ternary copper chalcogenides A/Cu/Q (A = Na, K, Rb, Cs, Tl; Q = S, Se, Te) are a family with rich structural and compositional diversity. These compounds host phase transitions, 1 modulated superlattices, [2][3] massive copper vacancies, [4][5] and are of interest in energy harvesting and conversion, including but not limited to: solid-state supercapacitors, [6][7] and ionic conductors. 8 All structural dimensionalities are found in this class, for example, the one-dimensional (1D) Na3Cu4S4, [9][10] the two-dimensional (2D) ACu4Q3 (A = Na, K, Rb, Cs, Tl; Q = S, Se), [11][12] NaCu4S4, 13 A4Cu8Te10 (A = Rb, Cs), 14 NaCu6Se4, 15 TlCu2Se2, 16 and the three-dimensional (3D) K4Cu8Te11, 14 Cs3Cu20Te13, 17 to name a few.…”

Synthesis and characterization of KCu3S2 microstructures through a composite-hydroxide mediated method

“…Hwu and coworkers proposed a one-dimensional diffusive ordering model that indicates that the phase transition is caused by vacancy ordering involving Cu + ion diffusion along the Cu(2)-Cu(2) zigzag chains. They validated this explanation through electron diffraction measurements [12][13][14]. However, some researchers have noticed that, although the structure of KCu 3 S 2 not only possesses the building blocks found in KCu 7 S 4 , it also possesses the layered structure of K 3 Cu 8 S 6 .…”