TY - JOUR
T1 - Systemic Study of Orbital and Spin Nematicity in NaFe1−xCoxAs by NMR
AU - Zhou, Rui
AU - Zheng, Guo qing
N1 - Funding Information:
This work was done in collaboration with L.Y. Xing, X. C. Wang, and C. Q. Jin of Institute of Physics. We thank S. Maeda and T. Oguchi for advice and help in the EFG calculation, Z. Li and J. Yang for assistance in some of the measurements. This work was partially supported by CAS Strategic Priority Research Program, No. XDB07020200 and by a 973 project National Basic Research Program of China, No. 2012CB821402.
Publisher Copyright:
© 2017, Springer Science+Business Media New York.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Nematic order, a self-organized state with rotational symmetry broken, has been observed in both copper-oxide and iron-pnictide high temperature superconductors. However, its origin is still a mystery in the iron pnictides although it is considered as a key to understand the mechanism of superconductivity. Here, we report a systemic nuclear magnetic resonance (NMR) study on NaFe1−xCoxAs (0 ≤x ≤ 0.042) that an orbital order, accompanied by an instant spin nematicity, occurs at at a temperature T∗ far above structural transition temperature Ts in the tetragonal phase. We show that the observed NMR spectra splitting and its evolution is due to an incommensurate orbital order that sets in below T∗ and becomes commensurate below Ts. We show that the electric field gradient asymmetry parameter is a good measure for the orbital order parameter which undergoes a Landau-like 2nd-order phase transition. We further show that the spin nematicity is well accounted for by the observed orbital order.
AB - Nematic order, a self-organized state with rotational symmetry broken, has been observed in both copper-oxide and iron-pnictide high temperature superconductors. However, its origin is still a mystery in the iron pnictides although it is considered as a key to understand the mechanism of superconductivity. Here, we report a systemic nuclear magnetic resonance (NMR) study on NaFe1−xCoxAs (0 ≤x ≤ 0.042) that an orbital order, accompanied by an instant spin nematicity, occurs at at a temperature T∗ far above structural transition temperature Ts in the tetragonal phase. We show that the observed NMR spectra splitting and its evolution is due to an incommensurate orbital order that sets in below T∗ and becomes commensurate below Ts. We show that the electric field gradient asymmetry parameter is a good measure for the orbital order parameter which undergoes a Landau-like 2nd-order phase transition. We further show that the spin nematicity is well accounted for by the observed orbital order.
KW - Iron pnictides
KW - Nematic order
KW - Nuclear magnetic resonance
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U2 - 10.1007/s10948-017-3997-5
DO - 10.1007/s10948-017-3997-5
M3 - Article
AN - SCOPUS:85013356434
VL - 30
SP - 857
EP - 863
JO - Journal of Superconductivity and Novel Magnetism
JF - Journal of Superconductivity and Novel Magnetism
SN - 1557-1939
IS - 4
ER -