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キーワード:
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要旨:
The hidden order (HO) in URu2Si2 has been determined as a high-rank
multipole formed by itinerant 5 f electrons with distinct orbital
structure imposed by the crystalline electric field. Because this can
lead to a considerable number of different multipoles, it is of great
importance to use microscopic techniques that are sensitive to their
subtle physical differences. Here, we investigate whether the
quasiparticle interference (QPI) method can distinguish between the two
most frequently proposed HO parameter models: the even rank-4
hexadecapole and the odd-rank-5 dotriacontapole model. We obtain the
quasiparticle dispersion and reconstructed Fermi surface in each HO
phase adapting an effective two-orbital model of 5 f bands that
reproduces the main Fermi surface sheets of the para phase. We show that
the resulting QPI spectrum reflects directly the effect of fourfold
symmetry breaking in the rank-5 model, which is absent in the rank-4
model. Therefore we suggest that the QPI method should give the
possibility of a direct discrimination between the two most investigated
models of HO in URu2Si2. Furthermore, the signature of proposed chiral
d-wave superconducting (SC) order parameter in QPI of the coexisting
HO+SC phase is investigated.
