Moissanite anvil cell single crystal NMR at pressures of up to 4.4 GPa

Kattinger, Carsten; Guehne, Robin; Tsankov, Stefan; Jurkutat, Michael; Erb, A.; Haase, J.

doi:10.1063/5.0065736

Cited by 3 publications

(1 citation statement)

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“…We became interested in this material because of the intriguing behavior under pressure, given our recent endeavor into high-pressure NMR studies of solids with anvil cells that currently allow studies under up to about 10 GPa (100 kbar) of pressure. − To obtain high sensitivity with the associated small sample that fits the pressure cell, we use radio-frequency (RF) microcoils inside the pressurized region. In fact, the first application with AgInTe 2 appeared to show an insulator-to-metal transition that we wanted to revisit.…”

Section: Introductionmentioning

confidence: 99%

NMR Study of AgInTe₂ at Normal and High Pressures

et al. 2022

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The ternary semiconductor AgInTe2 is a thermoelectric material with a chalcopyrite-type structure, which is believed to transform into a rocksalt-type structure under high pressure. Nuclear magnetic resonance (NMR) is considered to provide unique insight into material properties on interatomic length scales, especially in the context of structural phase transitions. Here, 115In and 125Te NMR analyses are used to study AgInTe2 for ambient conditions and pressures up to 5 GPa. Magnetic field-dependent and magic angle spinning (MAS) experiments of 125Te prove strongly enhanced internuclear couplings, as well as a distribution of isotropic chemical shifts, suggesting a certain degree of cation disorder. The indirect nuclear coupling is smaller for 115In, as well as the chemical shift distribution in agreement with the crystal structure. 115In NMR is further governed by a small quadrupolar interaction (ν Q ≈ 90 kHz) and shows an orders of magnitude faster nuclear relaxation in comparison to that of 125Te. At a pressure of about 3GPa, the 115In quadrupole interaction increases sharply to about 2400 kHz, indicating a phase transition to a structure with a well-defined though noncubic local symmetry, while the 115In shift suggests no significant changes of the electronic structure. The NMR signal is lost above about 5 GPa (at least up to about 10 GPa). However, upon releasing the pressure, a signal is recovered that points to the reported metastable ambient pressure phase with a high degree of disorder.

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Section: Introductionmentioning

confidence: 99%

NMR Study of AgInTe₂ at Normal and High Pressures

et al. 2022

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How pressure enhances the critical temperature of superconductivity in YBa ₂ Cu ₃ O _{6+
y}

Jurkutat

Kattinger

Tsankov

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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High-temperature superconducting cuprates respond to doping with a dome-like dependence of their critical temperature ( T c ). But the family-specific maximum T c can be surpassed by application of pressure, a compelling observation known for decades. We investigate the phenomenon with high-pressure anvil cell NMR and measure the charge content at planar Cu and O, and with it the doping of the ubiquitous CuO 2 plane with atomic-scale resolution. We find that pressure increases the overall hole doping, as widely assumed, but when it enhances T c above what can be achieved by doping, pressure leads to a hole redistribution favoring planar O. This is similar to the observation that the family-specific maximum T c is higher for materials where the hole content at planar O is higher at the expense of that at planar Cu. The latter reflects dependence of the maximum T c on the Cu–O bond covalence and the charge-transfer gap. The results presented here indicate that the pressure-induced enhancement of the maximum T c points to the same mechanism.

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