@article{que_visualizing_2025,

title = {Visualizing the internal structure of the charge-density-wave state in CeSbTe},

author = {X. Que and Q. He and L. Zhou and S. Lei and L. Schoop and D. Huang and H. Takagi},

url = {https://doi.org/10.1038/s41467-025-58417-x},

doi = {10.1038/s41467-025-58417-x},

year  = {2025},

date = {2025-03-28},

urldate = {2025-03-01},

journal = {Nat. Commun.},

volume = {16},

number = {1},

pages = {3053},

abstract = {The collective reorganization of electrons into a charge density wave has long served as a textbook example of an ordered phase in condensed matter physics. Two-dimensional square lattices with p electrons are well-suited to the realization of charge density waves, due to the anisotropy of the p orbitals and the resulting one dimensionality of the electronic structure. In spite of a long history of study of charge density waves in square-lattice systems, few reports have recognized the significance of a hidden orbital degree of freedom. The degeneracy of px and py electrons may give rise to orbital patterns in real space that endow the charge density wave with additional broken symmetries or unusual order parameters. Here, we use scanning tunneling microscopy to visualize the internal structure of the charge-density-wave state of CeSbTe, which contains Sb square lattices with 5p electrons. We image atomic-sized, anisotropic lobes of charge density with periodically modulating anisotropy, which we interpret in terms of a superposition of px and py bond density waves. Our results support the fact that delocalized p orbitals can reorganize into emergent electronic states of matter.},

keywords = {A3},

pubstate = {published},

tppubtype = {article}

}

@article{matsumoto_quantum_2024,

title = {A quantum critical Bose gas of magnons in the quasi-two-dimensional antiferromagnet YbCl_{3} under magnetic fields},

author = {Y. Matsumoto and S. Schnierer and J. A. N. Bruin and J. Nuss and P. Reiss and G. Jackeli and K. Kitagawa and H. Takagi},

url = {https://doi.org/10.1038/s41567-024-02498-w},

doi = {10.1038/s41567-024-02498-w},

year  = {2024},

date = {2024-05-09},

urldate = {2024-05-09},

journal = {Nat. Phys.},

volume = {20},

number = {7},

pages = {1131–1138},

abstract = {Bose–Einstein condensation (BEC) is a quantum phenomenon in which a macroscopic number of bosons occupy the lowest energy state and acquire coherence at low temperatures. In three-dimensional antiferromagnets, a magnetic-field-induced transition has been successfully described as a magnon BEC. For a strictly two-dimensional (2D) system, it is known that BEC cannot take place due to the presence of a finite density of states at zero energy. However, in a realistic quasi-2D magnet consisting of stacked magnetic layers, a small but finite interlayer coupling stabilizes marginal BEC but such that 2D physics is still expected to dominate. This 2D-limit BEC behaviour has been reported in a few materials but only at very high magnetic fields that are difficult to access. The honeycomb S = 1/2 Heisenberg antiferromagnet YbCl3 exhibits a transition to a fully polarized state at a relatively low in-plane magnetic field. Here, we demonstrate the formation of a quantum critical 2D Bose gas at the transition field, which, with lowering the field, experiences a BEC marginally stabilized by an extremely small interlayer coupling. Our observations establish YbCl3, previously a Kitaev quantum spin liquid material, as a realization of a quantum critical BEC in the 2D limit.},

keywords = {A3},

pubstate = {published},

tppubtype = {article}

}