TY - JOUR
T1 - Influence of disorder on the signature of the pseudogap and multigap superconducting behavior in FeSe
AU - Rößler, Sahana
AU - Huang, Chien Lung
AU - Jiao, Lin
AU - Koz, Cevriye
AU - Schwarz, Ulrich
AU - Wirth, Steffen
N1 - Funding Information:
We thank S.-L. Drechsler and U. K. Rößler for fascinating discussions. Financial support from the Deutsche Forschungsgemeinschaft (DFG) within the Schwerpunktprogramm SPP1458 is gratefully acknowledged. L.J. thanks the Alexander von Humboldt Foundation for financial support.
Funding Information:
We thank S.-L. Drechsler and U. K. Rößler for fascinating discussions. Financial support from the Deutsche Forschungsgemeinschaft (DFG) within the Schwerpunktprogramm SPP1458 is gratefully acknowledged. L.J. thanks the Alexander von Humboldt Foundation for financial support.
Publisher Copyright:
© 2018 American Physical Society.
PY - 2018/3/8
Y1 - 2018/3/8
N2 - We investigated several FeSe single crystals grown by two different methods by utilizing experimental techniques, namely, resistivity, magnetoresistance, specific heat, scanning tunneling microscopy, and spectroscopy. The residual resistivity ratio (RRR) shows systematic differences between samples grown by chemical vapor transport and flux vapor transport, indicating variance in the amount of scattering centers. Although the superconducting transition temperature Tc is not directly related to RRR, our study evidences subtle differences in the features of an incipient ordering mode related to a depletion of density of states at the Fermi level. For instance, the onset temperature of anisotropic spin fluctuations at T∗≈75 K, and the temperature of the opening up of a partial gap in the density of states at T∗∗≈30 K, are not discernible in the samples with lower RRR. Further, we show that the functional dependence of the electronic specific heat below 2 K, which allows us to determine the nodal features as well as the small superconducting gap, differs significantly in crystals grown by these two different methods. Our investigation suggests that some of the controversies about the driving mechanism for the superconducting gap or its structure and symmetry are related to minute differences in the crystals arising due to the growth techniques used and the total amount of scattering centers present in the sample.
AB - We investigated several FeSe single crystals grown by two different methods by utilizing experimental techniques, namely, resistivity, magnetoresistance, specific heat, scanning tunneling microscopy, and spectroscopy. The residual resistivity ratio (RRR) shows systematic differences between samples grown by chemical vapor transport and flux vapor transport, indicating variance in the amount of scattering centers. Although the superconducting transition temperature Tc is not directly related to RRR, our study evidences subtle differences in the features of an incipient ordering mode related to a depletion of density of states at the Fermi level. For instance, the onset temperature of anisotropic spin fluctuations at T∗≈75 K, and the temperature of the opening up of a partial gap in the density of states at T∗∗≈30 K, are not discernible in the samples with lower RRR. Further, we show that the functional dependence of the electronic specific heat below 2 K, which allows us to determine the nodal features as well as the small superconducting gap, differs significantly in crystals grown by these two different methods. Our investigation suggests that some of the controversies about the driving mechanism for the superconducting gap or its structure and symmetry are related to minute differences in the crystals arising due to the growth techniques used and the total amount of scattering centers present in the sample.
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U2 - 10.1103/PhysRevB.97.094503
DO - 10.1103/PhysRevB.97.094503
M3 - Article
AN - SCOPUS:85043995847
VL - 97
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 9
M1 - 094503
ER -