High-field superconductivity at an electronic topological transition in URhGe
High-field superconductivity at an electronic topological transition in URhGe
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DOI：
10.1038/nphys2073
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发表时间：
2011-07
期刊：
影响因子：
19.6
通讯作者：
E. Yelland;J. Barraclough;Weiwei Wang;K. Kamenev;A. Huxley
中科院分区：
文献类型：
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作者：
E. Yelland;J. Barraclough;Weiwei Wang;K. Kamenev;A. Huxley
在高磁场下超导电性的出现被认为是一个新的状态形成接近量子临界点的范例。到目前为止，准粒子质量在变磁转变时的发散被认为是超导性在30 T以上磁场中生存的必要条件。在这里，我们报告的量子振荡的观察URhGe揭示了一个小口袋的重准粒子，不断缩小，随着磁场的增加，并最终消失在一个拓扑费米表面过渡接近或在变磁场。准粒子质量减小并保持有限，这意味着费米速度由于费米波矢的坍缩而消失。这为极端磁场下超导性的重新出现提供了一个新的解释，并使URhGe成为第一个被证明的费米表面磁场调谐材料的例子，而不仅仅是量子临界性，决定了量子相的形成。
The emergence of superconductivity at high magnetic fields in URhGe is regarded as a paradigm for new state formation approaching a quantum critical point. Until now, a divergence of the quasiparticle mass at the metamagnetic transition was considered essential for superconductivity to survive at magnetic fields above 30 T. Here we report the observation of quantum oscillations in URhGe revealing a tiny pocket of heavy quasiparticles that shrinks continuously with increasing magnetic field, and finally disappears at a topological Fermi surface transition close to or at the metamagnetic field. The quasiparticle mass decreases and remains finite, implying that the Fermi velocity vanishes due to the collapse of the Fermi wavevector. This offers a novel explanation for the re-emergence of superconductivity at extreme magnetic fields and makes URhGe the first proven example of a material where magnetic field-tuning of the Fermi surface, rather than quantum criticality alone, governs quantum phase formation.