RSAVS superconductors: Materials with a superconducting state that is robust against large volume shrinkage
RSAVS superconductors: Materials with a superconducting state that is robust against large volume shrinkage
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RSAVS 超导体：具有超导状态的材料，可抵抗大体积收缩
DOI：
10.1103/physrevmaterials.4.071801
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发表时间：
2020-07-20
影响因子：
3.4
通讯作者：
Sun, Liling
中科院分区：
文献类型：
--
作者：
Huang, Cheng;Guo, Jing;Sun, Liling
正常态和超导态之间的转变温度(T-C)通常随着外加压力的增加而急剧增加或降低。相反，我们在这里展示了一种超导体的奇特特征，即T-C对外加压力引起的大体积收缩(RSAVS，因此将其命名为RSAVS超导体)具有很强的健壮性。特别的是，我们之前的研究发现，这两种材料的T-C在一个很大的压力范围内几乎保持不变，例如，(TaNb)(0.67)(HfZrTi)(0.33)高熵合金中的T-C超过136 Gpa，而在NbTi商业合金中，T-C几乎保持不变。在这里，我们证明了RSAVS行为也存在于另一种高熵合金(ScZrNbTa)(0.6)(RhPd)(0.4)以及超导元素Ta和Nb中，这表明这种行为普遍存在于一种只由过渡金属元素组成的体心立方晶格的超导体中。我们的电子结构计算表明，在RSAVS态下，简并d(x2-y2)和d(Z2)轨道电子在费米能级上的贡献几乎不变，这表明这些电子可能对稳定RSAVS态的T-C起着至关重要的作用。我们通过《宅基地法》初步分析了这一建议的合理性和有效性。
The transition temperature (T-C) between normal and superconducting states usually exhibits a dramatic increase or decrease with increasing applied pressure. Here we present, in contrast, a type of superconductor that exhibits the exotic feature that T-C is robust against large volume shrinkages (RSAVS, so naming them "RSAVS superconductors") induced by applied pressure. Extraordinarily, our previous studies found that the T-C in the two materials stays almost constant over a large pressure range, e.g., over 136 GPa in the (TaNb)(0.67)(HfZrTi)(0.33) high-entropy alloy and 141 GPa in the NbTi commercial alloy. Here, we show that the RSAVS behavior also exists in another high-entropy alloy, (ScZrNbTa)(0.6)(RhPd)(0.4), and in superconducting elemental Ta and Nb, indicating that this behavior occurs universally in a certain kind of superconductor, composed of only transition metal elements, with a body-centered cubic lattice. Our electronic structure calculations indicate that in the RSAVS state the contribution of the degenerate d(x2-y2) and d(z2) orbital electrons remains almost unchanged at the Fermi level, suggesting that these are the electrons that may play a crucial role in stabilizing the T-C in the RSAVS state. We preliminarily analyzed the reasonability and validity of this suggestion by the Homes law.