Field-induced quantum critical point in the itinerant antiferromagnet Ti3Cu4
Field-induced quantum critical point in the itinerant antiferromagnet Ti3Cu4
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DOI：
10.1038/s42005-022-00901-7
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发表时间：
2020-10
影响因子：
5.5
通讯作者：
J. M. Moya;A. Hallas;V. Loganathan;C. Huang;L. Kish;A. Aczel;J. Beare;Y. Cai;G. Luke;Franziska Weickert;A. Nevidomskyy;C. Malliakas;M. Kanatzidis;Shiming Lei;K. Bayliff;E. Morosan
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文献类型：
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作者：
J. M. Moya;A. Hallas;V. Loganathan;C. Huang;L. Kish;A. Aczel;J. Beare;Y. Cai;G. Luke;Franziska Weickert;A. Nevidomskyy;C. Malliakas;M. Kanatzidis;Shiming Lei;K. Bayliff;E. Morosan
新的物质相出现在磁不稳定性的边缘，这可能发生在具有局部化，巡回或介于这些极端之间的时刻的材料中。在局域矩系统中，如重费米子，磁性可以通过压力、化学掺杂和磁场（很少）在量子临界点（QCP）处朝向零温度转变。相比之下，在巡游矩系统中，QCP更罕见，它们是由压力或掺杂引起的;没有已知的场诱导跃迁的例子。这意味着在整个巡游矩到局域矩的范围内，还没有建立起普适的行为--这是我们对量子临界性的认识中的一个重大空白。在这里，我们报告了一个巡回反铁磁体，Ti 3Cu 4，可以通过一个小磁场调谐到QCP。我们看到的量子临界性和相关的非费米液体的热力学和运输测量行为的签名，而能带结构计算指向一个轨道选择性，自旋密度波基态，在Ti 3Cu 4的正方形净结构基序的后果。因此，Ti 3Cu 4提供了一个平台，用于比较和概括整个磁性光谱的量子临界行为。
New phases of matter emerge at the edge of magnetic instabilities, which can occur in materials with moments that are localized, itinerant or intermediate between these extremes. In local moment systems, such as heavy fermions, the magnetism can be tuned towards a zero-temperature transition at a quantum critical point (QCP) via pressure, chemical doping, and, rarely, magnetic field. By contrast, in itinerant moment systems, QCPs are more rare, and they are induced by pressure or doping; there are no known examples of field induced transitions. This means that no universal behaviour has been established across the whole itinerant-to-local moment range—a substantial gap in our knowledge of quantum criticality. Here we report an itinerant antiferromagnet, Ti3Cu4, that can be tuned to a QCP by a small magnetic field. We see signatures of quantum criticality and the associated non-Fermi liquid behaviour in thermodynamic and transport measurements, while band structure calculations point to an orbital-selective, spin density wave ground state, a consequence of the square net structural motif in Ti3Cu4. Ti3Cu4thus provides a platform for the comparison and generalisation of quantum critical behaviour across the whole spectrum of magnetism.