The transport and thermodynamic properties of β-ReO₂ crystallizing in a nonsymmorphic structure were studied using high-quality single crystals. An extremely large magnetoresistance (XMR) of 22,000% was observed in a transverse magnetic field of 10 T at 2 K. However, unlike other topological semimetals that show XMR, β-ReO₂ has a high electron carrier density of 1 × 10²² cm⁻³, as determined by Hall effect measurements and large Fermi surfaces in the electronic structure. In addition, a small Fermi surface with a small effective mass was evidenced by de Haas–van Alphen oscillation measurements. Previous band structure calculations [Wang, et al., Nat. Commun. 8, 1844 (2017)] revealed the existence of two types of loops made of Dirac points of hourglass-shaped dispersions that are connected to each other by a point to form a string of alternating loops, called a Dirac loop chain (DLC), which are protected by multiple glide symmetries. Our first-principles calculations revealed the complex Fermi surfaces, the smallest of which corresponds to the observed small Fermi surface, which is located near the DLC. The XMR of β-ReO₂ is attributed to the small Fermi surface, which is likely caused by the DLC.

中文翻译：

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沙漏狄拉克环链金属 β-ReO2 中的极大磁阻

使用高质量单晶研究了以非对称结构结晶的 β-ReO ₂的输运和热力学性质。在 2 K、10 T 的横向磁场中观察到 22,000% 的极大磁阻 (XMR)。然而，与其他显示 XMR 的拓扑半金属不同，β-ReO ₂具有 1 × 10 ²² cm的高电子载流子密度^-3，由霍尔效应测量和电子结构中的大费米面确定。此外，de Haas-van Alphen 振荡测量证明了具有小有效质量的小费米面。以前的能带结构计算 [Wang, et al., Nat. 社区。8, 1844 (2017)] 揭示了两种由沙漏形色散的狄拉克点组成的环的存在，这些环通过一个点相互连接形成一串交替的环，称为狄拉克环链 (DLC)，受到多重滑动对称性的保护。我们的第一性原理计算揭示了复杂的费米面，其中最小的对应于观察到的位于 DLC 附近的小费米面。β-ReO ₂的 XMR归因于小费米面，这可能是由 DLC 引起的。