NMR study of Ba8Cu5SixGe41−x clathrate semiconductors

Sirusi, Ali A.; Ross, Joseph H.; Yan, Xinlin; Paschen, S.

doi:10.1039/c5cp02575c

Cited by 7 publications

(2 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, TM elements and possible vacancies preferentially occupy the 6c site 17,21,23,24,36,37,[40][41][42][43] and avoid direct 13 element bonding. 14,18,19,38,44,45 Structural details can also be extracted from thermal parameters obtained by refining diffraction data or NMR measurements, 37,46 or from changes of interatomic distances induced by composition variations as shown here.…”

Section: Structure Analysis Of Single Crystalsmentioning

confidence: 99%

Suppression of vacancies boosts thermoelectric performance in type-I clathrates

et al. 2018

Self Cite

View full text Add to dashboard Cite

Intermetallic type-I clathrates continue to attract attention as promising thermoelectric materials. Here we present structural and thermoelectric properties of single crystalline Ba 8 (Cu,Ga,Ge,2) 46 , where 2 denotes a vacancy. By single crystal X-ray diffraction on crystals without Ga we find clear evidence for the presence of vacancies at the 6c site in the structure. With increasing Ga content, vacancies are successively filled. This increases the charge carrier mobility strongly, even within a small range of Ga substitution, leading to reduced electrical resistivity and enhanced thermoelectric performance. The largest figure of merit ZT = 0.9 at 900 K is found for a single crystal of approximate composition Ba 8 Cu 4.6 Ga 1.0 Ge 40.4 . This value, that may further increase at higher temperatures, is one of the largest to date found in transition metal element-based clathrates.

show abstract

Section: Structure Analysis Of Single Crystalsmentioning

confidence: 99%

Suppression of vacancies boosts thermoelectric performance in type-I clathrates

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both electronic properties and thermal conductivity need to be optimized. A “cross-substitution” could improve these properties by more flexibly changing the electronic band structure and introducing more scattering centers [8,26,37,38,39,40,41,42,43,44,45,46,47]. It brings in the meantime interest for the fundamental investigation on chemical properties such as structural variations and stabilities.…”

Section: Introductionmentioning

confidence: 99%

Crystal Chemistry and Thermoelectric Properties of Type-I Clathrate Ba8Ni∼3.8SixGe42.2−x (x = 0, 10, 20, 42.2)

et al. 2018

Self Cite

View full text Add to dashboard Cite

Thermoelectric materials are actively considered for waste heat recovery applications. To improve the heat to electricity conversion efficiency, fundamental understanding on composition, crystal structure, and interrelation with the thermoelectric properties is necessary. Here, we report the chemical and thermoelectric properties of type-I clathrates Ba8Ni3.8SixGe42.2−x (x = 0, 10, 20, 42.2), to show that the Si substitution can retain the low lattice thermal conductivity as in pure Ge-based clathrates by adding defects (cage distortion) scattering and/or alloying effect, and the charge carrier concentration can be optimized and thus the electronic properties can be improved by tailoring the vacancy content. We demonstrate the vacancies in the pure Ge-based compound by Rietveld refinement, and possible vacancies in the quaternary compound by transport property measurements. We also show that, for intrinsic property studies in these compounds with such a complex crystal structure, a heat treatment for as cast alloys is necessary for phase purity and composition homogeneity. The highest ZT value of 0.19 at 550 °normalC is reached in the compound with x=10.

show abstract

First‐Principles Computation ofNMRParameters in Solid‐State Chemistry

Cuny

Gautier

Halet

2017

Handbook of Solid State Chemistry

View full text Add to dashboard Cite

First‐principles calculations ofNMRparameters have been the subject of intense researches over the last decades both from a scientific challenge point of view and the importance of their applications in materials science. In particular, the last 15 years have seen fundamental breakthroughs in this domain with the development of several approaches specifically devoted to the calculation of NMR parameters such as quadrupolar couplings, chemical shifts, and J couplings in solid‐state systems. In this chapter, we will describe these different approaches highlighting their strengths, their limitations, and their range of applications. This will then be illustrated by a number of educational examples from different areas of materials science for which the synergy between theoretical calculations of NMR parameters and experimental studies have allowed to answer complex chemical topics.

show abstract

NMR study of Ba₈Cu₅Si_xGe_41−x clathrate semiconductors

Abstract: We have performed 63

Cited by 7 publications

References 33 publications

Suppression of vacancies boosts thermoelectric performance in type-I clathrates

Suppression of vacancies boosts thermoelectric performance in type-I clathrates

Crystal Chemistry and Thermoelectric Properties of Type-I Clathrate Ba8Ni∼3.8SixGe42.2−x (x = 0, 10, 20, 42.2)

First‐Principles Computation ofNMRParameters in Solid‐State Chemistry

Contact Info

Product

Resources

About