|Title||Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As-75 NMR/NQR measurements|
|Publication Type||Journal Article|
|Year of Publication||2014|
|Authors||Furukawa, Y, Roy, B, Ran, S, Bud'ko, SL, Canfield, PC|
|Journal||Physical Review B|
|Type of Article||Article|
The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As-75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T-1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As-75 NMR spectra, together with the T-independent behavior of magnetic susceptibility chi and the T dependence of 1/T1T chi, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.
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