论文标题
Kondo半学Cecu $ _ {1.11} $ as $ _2 $的各向异性物理特性
Anisotropic Physical Properties of the Kondo Semimetal CeCu$_{1.11}$As$_2$
论文作者
论文摘要
最近提出的名为Weyl-Kondo半学(WKSM)的新型材料类是时间逆转但反转对称性损坏的近代半学,其中weyl节点被近相互作用推向费米水平。在这里,我们探索CECU $ _ {1+x} $作为$ _2 $可能是新的WKSM候选人。我们报告其单晶的生长,结构确定和物理性质研究。先前发表的关于多晶样品的研究表明,它确实是近代半学,这是我们对单晶的研究证实的。 X射线衍射表明CECU $ _ {1+X} $作为$ _2 $在四方中心对称结构中结晶,尽管由于部分占据的Cu位点,反转对称性仍然可以在本地破坏。化学分析导致平均职业$ x $ = 0.11(1)。电阻率随温度降低而饱和10 k的对数增加。从霍尔效应实验中,提取了$ 8.8 \ times 10^{20} $ cm $^{ - 3} $的电荷载体密度,这是半学的值特征。磁化化显示出明显的各向异性,没有磁性订购至0.4 K的证据。因此,我们将CECU $ _ {1.11} $分类为$ _2 $,为四方昆多半毛,具有各向异性磁性属性,并具有可能破裂的倒置对称性,从而满足了必要的条件,从而满足了wksm的状态。
The recently proposed novel materials class called Weyl-Kondo semimetal (WKSM) is a time reversal invariant but inversion symmetry broken Kondo semimetal in which Weyl nodes are pushed to the Fermi level by the Kondo interaction. Here we explore whether CeCu$_{1+x}$As$_2$ may be a new WKSM candidate. We report on its single-crystal growth, structure determination and physical properties investigation. Previously published studies on polycrystalline samples suggest that it is indeed a Kondo semimetal, which is confirmed by our investigations on single crystals. X-ray diffraction reveals that CeCu$_{1+x}$As$_2$ crystallizes in a tetragonal centrosymmetric structure, although the inversion symmetry could still be broken locally due to partially occupied Cu sites. Chemical analysis results in an average occupation $x$ = 0.11(1). The electrical resistivity increases logarithmically with decreasing temperature, and saturates below 10 K. A Kondo temperature $T_{\mathrm{K}}$ $\approx$ 4 K is extracted from entropy, estimated from the specific heat measurements. From Hall effect experiments, a charge carrier density of $8.8 \times 10^{20}$ cm$^{-3}$ is extracted, a value characteristic of a semimetal. The magnetization shows pronounced anisotropy, with no evidence of magnetic ordering down to 0.4 K. We thus classify CeCu$_{1.11}$As$_2$ as a tetragonal Kondo semimetal with anisotropic magnetic properties, with a possibly broken inversion symmetry, thus fulfilling the necessary conditions for a WKSM state.