KFU. Card publication. Defect charging and resonant levels in half-Heusler Nb1−xTixFeSb

KAZAN
FEDERAL UNIVERSITY

- RUS
- 中文
- ES

DEFECT CHARGING AND RESONANT LEVELS IN HALF-HEUSLER NB1−XTIXFESB

Form of presentation

Other electronic educational resources

Year of publication

2020

Язык

английский

Authors, employees of KFU

Vagizov Farit Gabdulkhakovich, author

Other authors

Ghassemi Nader , author

Ren Wuyang , author

Ren Zhifeng , author

Ross Joseph H. , author

Tian Yefan , author

Wang Zhiming , author

Zhu Hangtian , author

Bibliographic description in the original language

Defect charging and resonant levels in half-Heusler Nb1−xTixFeSb / Y Tian, F G. Vagizov, N Ghassemi [at al.] // arxiv.org. - 2020. - P. 1-10. - https://arxiv.org/abs/1912.09643.pdf.

Annotation

We report Nb and Sb NMR and J Fe Mdssbauer studies combined with DFT calculations of Nbi-arTixFeSb (0 ^ x ^ 0.3), one of the most promising thermoelectric systems for applications above 1000 K. These studies provide local information about defects and electronic configurations in these heavily p-type materials. The NMR spin-lattice relaxation rate provides a measure of states within the valence band. With increasing x, changes of relaxation rate vs carrier concentration for different substitution fractions indicate the importance of resonant levels which do not contribute to charge transport. The local paramagnetic susceptibility is significantly larger than expected based on DFT calculations, which we discuss in terms of an enhancement of the susceptibility due to a Coulomb enhancement mechanism. The Mossbauer spectra of Ti-substituted samples show small departures from a binomial distribution of substituted atoms, while for unsubstituted p-type NbFeSb, the amplitude of a Mossbauer satellite peak increases vs temperature, a measure of the T-dependent charging of a population of defects residing about 30 meV above the valence band edge, indicative of an impurity band at this location.

Keywords

Mossbauer spectroscopy, NMR, half-Heusler allows, defect charging

On-line resource for training course

http://dspace.kpfu.ru/xmlui/bitstream/handle/net/158969/F_Vagizov_arxiv_Defect_charging.pdf?sequence=1&isAllowed=y

URL

https://arxiv.org/abs/1912.09643.pdf

Please use this ID to quote from or refer to the card

https://repository.kpfu.ru/eng/?p_id=234683&p_lang=2

Resource files

File name	Size (MB)	Format
F_Vagizov_arxiv_Defect_charging.pdf	1,03	pdf	show / download

Full metadata record

Field DC	Value	Language
dc.contributor.author	Vagizov Farit Gabdulkhakovich	ru_RU
dc.contributor.author	Ghassemi Nader	ru_RU
dc.contributor.author	Ren Wuyang	ru_RU
dc.contributor.author	Ren Zhifeng	ru_RU
dc.contributor.author	Ross Joseph H.	ru_RU
dc.contributor.author	Tian Yefan	ru_RU
dc.contributor.author	Wang Zhiming	ru_RU
dc.contributor.author	Zhu Hangtian	ru_RU
dc.date.accessioned	2020-01-01T00:00:00Z	ru_RU
dc.date.available	2020-01-01T00:00:00Z	ru_RU
dc.date.issued	2020	ru_RU
dc.identifier.citation	Defect charging and resonant levels in half-Heusler Nb1−xTixFeSb / Y Tian, F G. Vagizov, N Ghassemi [at al.] // arxiv.org. - 2020. - P. 1-10. - https://arxiv.org/abs/1912.09643.pdf.	ru_RU
dc.identifier.uri	https://repository.kpfu.ru/eng/?p_id=234683&p_lang=2	ru_RU
dc.description.abstract	We report Nb and Sb NMR and J Fe Mdssbauer studies combined with DFT calculations of Nbi-arTixFeSb (0 ^ x ^ 0.3), one of the most promising thermoelectric systems for applications above 1000 K. These studies provide local information about defects and electronic configurations in these heavily p-type materials. The NMR spin-lattice relaxation rate provides a measure of states within the valence band. With increasing x, changes of relaxation rate vs carrier concentration for different substitution fractions indicate the importance of resonant levels which do not contribute to charge transport. The local paramagnetic susceptibility is significantly larger than expected based on DFT calculations, which we discuss in terms of an enhancement of the susceptibility due to a Coulomb enhancement mechanism. The Mossbauer spectra of Ti-substituted samples show small departures from a binomial distribution of substituted atoms, while for unsubstituted p-type NbFeSb, the amplitude of a Mossbauer satellite peak increases vs temperature, a measure of the T-dependent charging of a population of defects residing about 30 meV above the valence band edge, indicative of an impurity band at this location.	ru_RU
dc.language.iso	ru	ru_RU
dc.subject	Mossbauer spectroscopy	ru_RU
dc.subject	NMR	ru_RU
dc.subject	half-Heusler allows	ru_RU
dc.subject	defect charging	ru_RU
dc.subject	Mossbauer spectroscopy	ru_RU
dc.subject	NMR	ru_RU
dc.subject	half-Heusler allows	ru_RU
dc.subject	defect charging	ru_RU
dc.title	Defect charging and resonant levels in half-Heusler Nb1−xTixFeSb	ru_RU
dc.type	Other electronic educational resources	ru_RU