Crystal structure and lattice dynamics of superionic copper selenide Cu2−δSe

Danilkin, Sergey; Skomorokhov, A. N.; Hoser, A.; Fueß, H.; Rajevac, V.; Bickulova, N. N.

doi:10.1016/s0925-8388(03)00439-0

Cited by 74 publications

(56 citation statements)

References 9 publications

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“…To clarify the situation measurements of the phonon density of states have been performed in Cu 1.78 Se and Cu 2 Se powder samples using a multidetector time-of flight spectrometer. 5). We observed that the intensity of the low-energy peaks changes strongly with scattering angle.…”

Section: Introductionmentioning

confidence: 70%

“…An acoustic origin of the low-energy mode was confirmed by inelastic neutron scattering measurements with a Cu 1.85 Se single crystal sample. 5). It was found that the measured dispersion curves of the transverse acoustic (TA) phonons show a drastic change in the slope and flatten out at phonon wave vectors q > 0.4 with an energy of about 4 meV.…”

Section: Introductionmentioning

confidence: 97%

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Phonon Dispersion in Superionic Copper Selenide: Observation of Soft Phonon Modes in Superionic Phase Transition

2010

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This paper reports lattice dynamical measurements of Cu 1.8 Se superionic conductor in the superionic -phase at ambient temperature. Measurements of phonon dispersion curves were performed with the new triple-axis spectrometer, TAIPAN, at the OPAL reactor. We found that TA [100], TA [111] and TA 1 [110] phonon branches demonstrate a decrease in frequency at wavevectors q > 0.5 rather than the flattening observed previously. Results are compared with calculated density functional theoretical calculations showing the presence of unstable soft mode related to ordering of Cu atoms observed in Cu 1.8 Se at room temperature followed byphase transition at a lower temperature. Superstructure arising from the ordering causes effects similar to the folding of the Brillouin zone, although phonon intensities at new Brillouin zone centres are weak. The coupling of low-energy phonon modes with displacement of mobile ions can explain the strong damping of phonons at q > 0.5 observed in the experiment.

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Section: Introductionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 97%

Phonon Dispersion in Superionic Copper Selenide: Observation of Soft Phonon Modes in Superionic Phase Transition

2010

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“…[12], using a chemical bath deposition method, Garcia et al obtained the Cu 1.85 Se phase corresponding to the mineral berzelianite (JCPDS card 06-0680). Danilkin et al [17] produced the low temperature monoclinic β-Cu 2 Se phase using solid state reactions. We also investigated these possibilities but Rietveld refinements using these structures did not furnish good results.…”

Section: Methodsmentioning

confidence: 99%

“…A solar cell (Schottky type) employing a semi-transparent layer of Cu 2−x Se as window material on ntype semiconductor is estimated to have excellent photovoltaic properties and conversion efficiency around 9 % [9]. Many preparation methods of Cu 2−x Se alloys have been reported including sonochemical syntesis [10,11], chemical bath deposition [12,13,14], photochemical route [15], γ-irradiation [16], solid state reaction [17], microwave assisted heating [18], hydrothermal method [19], electrodeposition [20,21] and Mechanical Alloying (MA) [22].…”

Section: Introductionmentioning

confidence: 99%

“…The crystalline structure of Cu 2−x Se has been studied several times [17,23,24,25,26,27,28,29,30] but the precise distribution of Cu ions and the structure itself are still under discussion and diverging crystallographic data can be found in the literature. Rahlfs [23] and Borchert [24] proposed a structural model for α-Cu 2−x Se consisting of a cage of F43m symmetry, built by Se atoms in 4(a) sites and Cu ions in 4(c) sites, and a mobile cation subsystem formed by the remaining Cu ions distributed over the interstitial sites (tetrahedral 4(d), octahedral 4(b), and trigonal 16(e) sites).…”

Section: Introductionmentioning

confidence: 99%

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Structural study of CoxGe100−x alloys produced by mechanical alloying

Machado

Malfatti-Gasperini

Souza

et al. 2005

Solid State Communications

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The crystalline structures of superionic high temperature copper selenides Cu 2−x Se (0 ≤ x ≤ 0.25) produced by Mechanical Alloying were investigated using X-ray diffraction (XRD) technique. The measured XRD patterns showed the presence of the peaks corresponding to the crystalline superionic high temperature α-Cu 2 Se phase in the as-milled sample, and its structural data were determined by means of a Rietveld refinement procedure. After a heat treatment in argon at 200 • C for 90 h, this phase transforms to the superionic high temperature α-Cu 1.8 Se phase, whose structural data where also determined through the Rietveld refinement. In this phase, a very low occupation of the trigonal 32(f) sites (∼ 3%) by Cu ions is found. In order to explain the evolution of the phases in the samples, two possible mechanisms are suggested: the high mobility of Cu ions in superionic phases and the intense diffusive processes in the interfacial component of samples produced by Mechanical Alloying.

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Recent Advances in Liquid‐Like Thermoelectric Materials

Zhao

Qiu

Shi

et al. 2019

Adv Funct Materials

196

124

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Thermoelectric technology has attracted great attention due to its ability to recover and convert waste heat into readily available electric energy. Among the various candidate materials, liquid‐like compounds have received tremendous research interest on account of their intrinsically ultralow lattice thermal conductivity, tunable electrical properties, and high thermoelectric performance. Despite their complex phase transitions and diverse crystal structures, liquid‐like materials have two independent sublattices in common: one rigid sublattice formed by immobile ions for the free transport of electrons and one liquid‐like sublattice consisting of highly mobile ions to interrupt the thermal transports. This review first outlines the common structural features of liquid‐like thermoelectrics, along with their unusual electron and phonon transport behaviors that well satisfy the concept of “phonon‐liquid electron‐crystal.” Next, some commonly adopted strategies for further improving their thermoelectric performance are highlighted. The main progress achieved in the typical liquid‐like TE materials is then summarized, with an emphasis on their diverse crystal structures, common characteristics, and unique transport properties. The recent understandings on the stability issue of liquid‐like TE materials are also introduced. Finally, an outlook is given for the liquid‐like materials with the aim to boost further development in this exciting scientific subfield.

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Crystal structure and lattice dynamics of superionic copper selenide Cu2−δSe

Cited by 74 publications

References 9 publications

Phonon Dispersion in Superionic Copper Selenide: Observation of Soft Phonon Modes in Superionic Phase Transition

Phonon Dispersion in Superionic Copper Selenide: Observation of Soft Phonon Modes in Superionic Phase Transition

Structural study of CoxGe100−x alloys produced by mechanical alloying

Recent Advances in Liquid‐Like Thermoelectric Materials

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