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Title: From hidden order to antiferromagnetism: Electronic structure changes in Fe-doped URu 2 Si 2
In matter, any spontaneous symmetry breaking induces a phase transition characterized by an order parameter, such as the magnetization vector in ferromagnets, or a macroscopic many-electron wave function in superconductors. Phase transitions with unknown order parameter are rare but extremely appealing, as they may lead to novel physics. An emblematic and still unsolved example is the transition of the heavy fermion compound U R u 2 S i 2 (URS) into the so-called hidden-order (HO) phase when the temperature drops below T 0 = 17.5 K. Here, we show that the interaction between the heavy fermion and the conduction band states near the Fermi level has a key role in the emergence of the HO phase. Using angle-resolved photoemission spectroscopy, we find that while the Fermi surfaces of the HO and of a neighboring antiferromagnetic (AFM) phase of well-defined order parameter have the same topography, they differ in the size of some, but not all, of their electron pockets. Such a nonrigid change of the electronic structure indicates that a change in the interaction strength between states near the Fermi level is a crucial ingredient for the HO to AFM phase transition.
Authors:
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Award ID(s):
1810310
Publication Date:
NSF-PAR ID:
10288884
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
118
Issue:
27
Page Range or eLocation-ID:
e2020750118
ISSN:
0027-8424
Sponsoring Org:
National Science Foundation
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