kagome材料PrIr$_3$B$_2$中结构相变和磁相变的可调性
Tunability of the structural and magnetic transition in kagome material: PrIr$_3$B$_2$
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中文总结 AI 辅助
本研究通过同步辐射X射线衍射，发现kagome材料PrIr$_3$B$_2$的结构与磁相变可通过温度和压力调节，并揭示了与两步MIM相变相关的异常及可能的电荷有序态。
中文摘要 AI 辅助
我们利用同步辐射X射线粉末衍射，报道了kagome晶格化合物PrIr$_3$B$_2$中与两步金属-绝缘体-金属（MIM）相变相关的异常结构转变在温度和压力下的可调性。在环境温度和压力下，单斜（$C2/m$）和六方（$P6/mmm$）相以孪晶结构共存于晶体中。随着温度降低（或压力增加），PrIr$_3$B$_2$在$T =$ 280 K（环境压力下）和$P =$ 1.2 GPa（室温下）完全转变为单斜结构。环境压力下单斜结构的温度依赖性呈现出晶格参数的复杂演化，在约250 K和约110 K处出现微弱但清晰可辨的异常，分别与第二次MIM相变和线性到非线性温度依赖性电阻率的交叉相关。这些异常可能源于某种电荷有序态，导致费米面部分打开能隙。我们还通过各向异性测量研究了PrIr$_3$B$_2$的磁相图。在10 K时，超区能隙在反铁磁相变附近打开，即使在极化态下也不闭合。从晶体结构以及磁性和电子基态的可调性来看，这种kagome金属磁体中显示出有前景的电子有序态。
英文摘要
We report the temperature and pressure tunability of an unusual structural transformation associated with a two-step metal-insulator-metal (MIM) transition in the kagome lattice compound PrIr$_3$B$_2$ using synchrotron X-ray powder diffraction. At ambient conditions of temperature and pressure, the monoclinic ($C2/m$) and the hexagonal ($P6/mmm$) phases coexist as twinned structure in the crystal. As the temperature (pressure) is decreased (increased), PrIr$_3$B$_2$ converts fully to monoclinic structure at $T =$ 280 K (at ambient pressure) and $P =$ 1.2 GPa (at room temperature). Temperature dependence of the monoclinic structure at ambient pressure presents complex evolution of lattice parameters with weak but clearly discernable anomalies at \SI{\sim 250} {\K} and \SI{\sim 110} {\K}, which are correlated with the second MIM transition and the linear to nonlinear temperature-dependent resistivity crossover, respectively. These anomalies are likely due to some charge order state causing a partially gapped Fermi surface. The magnetic phase diagram of PrIr$_3$B$_2$ is also investigated from anisotropic measurements. At 10 K, a superzone gap opens near the antiferromagnetic transition, which does not close even in the polarized state. From the tunability of the crystal structure and magnetic and electronic ground state, promising electronic orders are indicated in this kagome metallic magnet.
发表机构
- Indian Institute of Technology Palakkad（印度理工学院帕拉克卡德分校）
- Elettra-Sincrotrone Trieste S.C.p.A.（的里雅斯特电子同步辐射中心）
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