Quantum matter in high magnetic fields

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Evidence for unidirectional nematic bond ordering in FeSe

(2016)

Authors:

MD Watson, TK Kim, LC Rhodes, M Eschrig, M Hoesch, AA Haghighirad, AI Coldea

Publisher’s Note: Dichotomy between the Hole and Electron Behavior in Multiband Superconductor FeSe Probed by Ultrahigh Magnetic Fields [Phys. Rev. Lett. 115, 027006 (2015)]

Physical Review Letters American Physical Society (APS) 115:21 (2015) 219902

Authors:

MD Watson, T Yamashita, S Kasahara, W Knafo, M Nardone, J Béard, F Hardy, A McCollam, A Narayanan, SF Blake, T Wolf, AA Haghighirad, C Meingast, AJ Schofield, HV L?hneysen, Y Matsuda, AI Coldea, T Shibauchi

17aDB-10 Fe(Se,S)の秩序相における量子振動とベリー位相の観測

(2015) 1784

Authors:

笠原 成, 山下 卓也, 下山 祐介, 綿重 達哉, 芝内 孝禎, 松田 祐司, William Knafo, Jerome Beard, Marc Nardone, Matthew Watoson, Amalia Coldea, Christoph Meingast, Thomas Wolf, Hilbert V Lohneysen

Suppression of orbital ordering by chemical pressure in FeSe1-xSx

(2015)

Authors:

MD Watson, TK Kim, AA Haghighirad, SF Blake, NR Davies, M Hoesch, T Wolf, AI Coldea

Suppression of orbital ordering by chemical pressure in FeSe1-xSx

Phys. Rev. B 92, 121108(R) (2015) (2015)

Authors:

MD Watson, TK Kim, AA Haghighirad, SF Blake, NR Davies, M Hoesch, T Wolf, AI Coldea

Abstract:

We report a high-resolution angle-resolved photo-emission spectroscopy study of the evolution of the electronic structure of FeSe1-xSx single crystals. Isovalent S substitution onto the Se site constitutes a chemical pressure which subtly modifies the electronic structure of FeSe at high temperatures and induces a suppression of the tetragonal-symmetry-breaking structural transition temperature from 87K to 58K for x=0.15. With increasing S substitution, we find smaller splitting between bands with dyz and dxz orbital character and weaker anisotropic distortions of the low temperature Fermi surfaces. These effects evolve systematically as a function of both S substitution and temperature, providing strong evidence that an orbital ordering is the underlying order parameter of the structural transition in FeSe1-xSx. Finally, we detect the small inner hole pocket for x=0.12, which is pushed below the Fermi level in the orbitally-ordered low temperature Fermi surface of FeSe.