LaCo2B2: a Co-based layered superconductor with a ThCr2Si2-type structure.
LaCo2B2: a Co-based layered superconductor with a ThCr2Si2-type structure.
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DOI：
10.1103/physrevlett.106.237001
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发表时间：
2011-03
影响因子：
8.6
通讯作者：
H. Mizoguchi;T. Kuroda;T. Kamiya;H. Hosono
中科院分区：
文献类型：
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作者：
H. Mizoguchi;T. Kuroda;T. Kamiya;H. Hosono
LaCo(2)B(2) 具有由交替堆叠的 La 和 CoB 层组成的 ThCr(2)Si(2) 型（所谓的“122”）结构，在低至 2 K 时表现出金属导电性和泡利顺磁行为。在用掺杂元素取代时，即等价取代形成 T(c) 为~4 K 的体超导性。 (La(1-x)Y(x))Co(2)B(2)，或异价取代形成La(Co(1-x)Fe(x))(2)B(2)。根据密度泛函理论计算，即使在未掺杂的样品中，占主导地位的费米能级的 Co 3d 和比费米能级更深的 B 2p 能级之间的高度共价键也消除了 Co 3d 电子的磁有序性。这是122型家族中第一个钴基超导体。
LaCo(2)B(2) with a ThCr(2)Si(2)-type (so-called "122") structure composed of alternately stacked La and CoB layers exhibits metallic electrical conductivity and Pauli paramagnetic behavior down to 2 K. Bulk superconductivity with a T(c) of ∼4 K emerges upon substituting with dopant elements, i.e., isovalent substitution to form (La(1-x)Y(x))Co(2)B(2), or aliovalent substitution to form La(Co(1-x)Fe(x))(2)B(2). According to the density functional theory calculations, highly covalent bonding between Co 3d dominating the Fermi level and B 2p levels deeper than the Fermi level removes magnetic ordering from Co 3d electrons even in the undoped samples. This is a first Co-based superconductor among the 122-type family.