Magnetic-Field-Induced Kondo Metal Realized in YbB12
Magnetic-Field-Induced Kondo Metal Realized in YbB12
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DOI：
10.1103/physrevlett.120.257206
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发表时间：
2018-06-22
影响因子：
8.6
通讯作者：
Iga, Fumitoshi
中科院分区：
文献类型：
--
作者：
Terashima, Taku T.;Matsuda, Yasuhiro H.;Iga, Fumitoshi
Kondo 绝缘体 YbB12 的比热经测量高达 60 T。索末菲系数 y 在 50 T 左右显着增加，其中绝缘体金属转变随着磁化强度的急剧增加而发生。 γ在高场下达到67 mJ/(mol K-2)，这直接表明准粒子获得了重的热力学有效质量并在磁场下转变为近藤金属。场诱导的近藤金属具有相当高的近藤温度，约为 200 K。强近藤耦合证明能隙塌缩并不对应于近藤束缚态的击穿。转变时磁化强度的急剧增加表明通过近藤共振形成的费米能态密度急剧增加。
The specific heat of the Kondo insulator YbB12 has been measured up to 60 T. The Sommerfeld coefficient y significantly increases at around 50 T, where the insulator metal transition occurs with a steep increase of the magnetization. gamma reaches 67 mJ/(mol K-2) at high fields, which directly indicates that the quasiparticles gain a heavy thermodynamic effective mass and transform into a Kondo metal under magnetic fields. The field-induced Kondo metal has a rather high Kondo temperature around 200 K. The strong Kondo coupling proves that the energy gap collapse does not correspond to the breakdown of the Kondo bound state. The steep increase of the magnetization at the transition manifests the sharp density of states at the Fermi energy formed via the Kondo resonance.