Electronic properties of GeTe and Ag- or Sb-substituted GeTe studied by low-temperature NMR
- Ames Lab. and Iowa State Univ., Ames, IA (United States); Iowa State Univ., Ames, IA (United States). Dept. of Chemistry
- Ames Lab. and Iowa State Univ., Ames, IA (United States); Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
- Ames Lab. and Iowa State Univ., Ames, IA (United States)
We have carried out 125Te nuclear magnetic resonance (NMR) in a wide temperature range of 1.5–300 K to investigate the electronic properties of Ge50 Te50, Ag2 Ge48Te50 , and Sb2 Ge48 Te50 from a microscopic point of view. From the temperature dependence of the NMR shift (K) and nuclear spin lattice relaxation rate (1/T1), we found that two bands contribute to the physical properties of the materials. One band overlaps the Fermi level providing the metallic state where no strong electron correlations are revealed by Korringa analysis. The other band is separated from the Fermi level by an energy gap of Eg/kB ~67 K, which gives rise to semiconductorlike properties. First-principles calculation reveals that the metallic band originates from the Ge vacancy while the semiconductorlike band is related to the fine structure of the density of states near the Fermi level. We find low-temperature Te125 NMR data for the materials studied here clearly show that Ag substitution increases hole concentration while Sb substitution decreases it.
- Research Organization:
- Ames Laboratory (AMES), Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-07CH11358
- OSTI ID:
- 1326845
- Alternate ID(s):
- OSTI ID: 1298343
- Report Number(s):
- IS-J-9078; PRBMDO; TRN: US1700098
- Journal Information:
- Physical Review B, Vol. 94, Issue 8; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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