Devil's staircase transition of the electronic structures in CeSb

Kenta Kuroda,M Sakano,Masashi Tokunaga ,Cédric Bareille ,Shunsuke Sakuragi ,S Akebi,So Kunisada ,Kakuhiro Kawaguchi ,Kozo Okazaki ,Mojtaba Alaei ,Ryo Noguchi ,Michihiro Nakayama ,S Ideta,H Suzuki ,Ryotaro Arita ,Shik Shin ,Yoshinori Haga ,Masashi Arita ,Yutaro Arai ,Yoshiki Kinoshita ,Nafise Rezaei ,Hideaki Kitazawa ,Kiyohisa Tanaka ,Takeshi Kondo

doi:10.1038/s41467-020-16707-6

Abstract

Solids with competing interactions often undergo complex phase transitions with a variety of long-periodic modulations. Among such transition, devil’s staircase is the most complex phenomenon, and for it, CeSb is the most famous material, where a number of the distinct phases with long-periodic magnetostructures sequentially appear below the Néel temperature. An evolution of the low-energy electronic structure going through the devil’s staircase is of special interest, which has, however, been elusive so far despite 40 years of intense research. Here, we use bulk-sensitive angle-resolved photoemission spectroscopy and reveal the devil’s staircase transition of the electronic structures. The magnetic reconstruction dramatically alters the band dispersions at each transition. Moreover, we find that the well-defined band picture largely collapses around the Fermi energy under the long-periodic modulation of the transitional phase, while it recovers at the transition into the lowest-temperature ground state. Our data provide the first direct evidence for a significant reorganization of the electronic structures and spectral functions occurring during the devil’s staircase.

Highlights

Solids with competing interactions often undergo complex phase transitions with a variety of long-periodic modulations
Let us start by showing that the tetragonal transition across TN forms multiple domains randomly distributed in the crystal at zero-field
It is necessary to discriminate these tetragonal domains in measurements by macroscopic probes such as angleresolved photoemission spectroscopy (ARPES); otherwise, the mixture of the signatures from the domains obscures the intrinsic electronic properties

Summary

Results

The clear signatures for the reconstruction are presented in the laser-ARPES maps (Fig. 3h, i) obtained at 7.0 K below TAF (AF phase) at the different positions of the same cleaved surface. These results unveil the dramatic reconstruction of the itinerant bands, which fully converts the electronic periodicity from cubic to tetragonal symmetry.

K kx kz ky (Å–1) E–EF (eV)

K Main hole band

Methods