科研之友
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摘要
Unlike the other prominent macroscopic spin-paired quantum state, superconductivity, where the focus is on the strongest coupling within a class, untuned weak magnetism presents an intellectual frontier where electronic structure, magnetic coupling, and (quantum and thermal) fluctuations provide a platform for unconventional phenomena. With a strong van Hove singularity (vHs) at the Fermi energy, TiAu (with no magnetic element) is highly unstable toward ferromagnetism, yet orders antiferromagnetically at a wave vector unrelated to Fermi surface nesting. We show that mirrored vHs provide the long-wavelength, low-frequency fluctuations characteristic of a wFM rather than that of a conventional wAFM, whereby wAFM competes on equal terms with wFM for the broken symmetry ordered state. Peierls-like energy gain from cell doubling can help promote wAFM, which is evident in TiAu.
- 出版日期2016-10
