Shubnikov-de Haas量子振荡揭示了在铜氧化物超导体Pr $_{1.86}$ Ce $_{0.14}$ CuO $_{4\pmδ}$薄膜中接近最佳掺杂的重构费米面
Shubnikov-de Haas quantum oscilations reveal a reconstructed Fermi surface near optimal doping in a thin film of the cuprate superconductor Pr$_{1.86}$Ce$_{0.14}$CuO$_{4\pmδ}$
Nicholas P. Breznay, Ian M. Hayes, B. J. Ramshaw, Ross D. McDonald, Yoshiharu Krockenberger, Ai Ikeda, Hiroshi Irie, Hideki Yamamoto, James G. Analytis
We study magnetotransport properties of the electron-doped superconductor Pr$_{2-x}$Ce$_x$CuO$_{4\pmδ}$ with $x$ = 0.14 in magnetic fields up to 92~T, and observe Shubnikov de-Haas magnetic quantum oscillations. The oscillations display a single frequency $F$=255$\pm$10~T, indicating a small Fermi pocket that is $\sim$~1\% of the two-dimensional Brillouin zone and consistent with a Fermi surface reconstructed from the large hole-like cylinder predicted for these layered materials. Despite the low nominal doping, all electronic properties including the effective mass and Hall effect are consistent with overdoped compounds. Our study demonstrates that the exceptional chemical control afforded by high quality thin films will enable Fermi surface studies deep into the overdoped cuprate phase diagram.
Shubnikov-de Haas effect and Yamaji oscillations in the antiferromagnetically ordered organic superconductor k-(BETS)2FeBr4: A Fermiology study
在有机超导体$κ$ -（BETS）$_2$ FeBr $_4$中观察到了Shubnikov-De Haas效应（SdH）和角相关磁电阻振荡（AMRO）。与其同构化合物$κ-(BETS)$ _2 $FeCl$ _4 $, SdH oscillations, for fields perpendicular to the conducting planes, reveal three Fermi Surface (FS) closed orbits $ α $, $ β $, and $ γ $ whose cross sectional areas are 19.8 %, 99.9 %, and 2.4 % of the first Brillouin zone, respectively. The conduction electron effective masses were found to be: $ μ_α =（4.7 \pm 0.2）$ m$ _e $, $ μ_β =（8.0 \pm 1.0）$ m$ _e $, and $ μ_γ =（2.0 \pm 0.2）$ m$ _e $. The observation of a $ γ $ orbit is not expected from band structure calculations, $ μ_β $ is …
本文报道了在欠掺杂铜氧化物超导体YBa $_2$ Cu $_4$ O $_8$（Y 124）中观察到的Shubnikov-de Haas振荡。对于沿c轴排列的场，振荡的频率是$660\pm 30$ T，其对应于第一布里渊区的总面积的$\sim 2.4$ %。这个轨道上准粒子的有效质量被测量为$2.7\pm0.3$乘以自由电子质量。频率和质量都与最近观察到的ortho-II YBa $_2$ Cu $_3$ O $_{6.5}$（Y123-II）相当。我们表明，虽然小费米表面口袋可以预期从能带结构计算在Y123-II，没有这样的口袋预测Y124。因此，我们的研究结果意味着这些小口袋是一个通用的功能的氧化铜平面在欠掺杂的铜酸盐。
Complete Fermi surface in BaFe$_2$As$_2$ observed via Shubnikov-de Haas oscillation measurements on detwinned single crystals
结果表明，BaFe $_2$ As $_2$反铁磁相的费米面（FS）由一个空穴和两个电子袋组成，它们都是三维的封闭的，与角分辨光电子能谱所观察到的FS形成鲜明对比.载波补偿和索末菲系数的考虑排除了未观察到的FS口袋的存在。一个标准的能带结构计算合理占所观察到的FS，尽管高估了有序矩。质量增强，即有效质量与能带质量之比，为2- 3。
de Haas-van Alphen oscillations in the underdoped cuprate YBa$_2$Cu$_3$O$_{6.5}$
利用转矩技术在高达59 T的脉冲磁场中观察到欠掺杂铜氧化物YBa $_2$ Cu $_3$ O $_{6.5}$的de Haas van Alphen效应。在$\sim$ 30 T的不可逆性场以上，磁化强度表现出明显的量子振荡，单频为540 T，回旋质量为自由电子质量的1.76倍，与先前观察到的Shubnikov-de Haas振荡非常一致。振荡遵循费米液体理论的标准Lifshitz-Kosevich公式。这种量子振荡的热力学观测证实了在铜酸盐的赝能隙相中存在一个定义明确、紧密且相干的费米面。
Quantum oscillations from `open' Fermi surface in quasi-one-dimensional lattices: Application to YBa2Cu3O6 cuprates, organic salts, ladder compounds, and related systems
根据著名的Onsagar-Lifshitz范式，Shubnikov de-Haas和de-Haas van Alphen（SdHvA）振荡的观察表明，在体中存在“闭合”轨道费米面。我们提出了一个基于实空间的计算SdHvA振荡在广义准一维晶格放松的准经典近似嵌入在这个几十年的老Onsagar-Lifshitz范式。我们发现，相当大的量子振荡可以产生从'开放'费米表面，只要回旋轨道可以形成在现实空间中有限的，但不一定相等，电子跳跃沿x和y方向。我们的结果定量地解释了各种准一维材料中令人困惑的SdHvA振荡的出现，包括YBa_2Cu_3O_6铜酸盐的链态，有机材料，各种梯形化合物，弱耦合线性链，或量子线，和其他相关系统。
