本文报道了KFe $_2$ As $_2$的能带结构计算和de Haas-van Alphen测量。电子的有效质量为6 ~ 18 $m_e$，其中$m_e$为自由电子的质量。计算的费米表面积和观测的费米表面积之间的显著差异以及大质量增强（$\gtrsim 3$）突出了电子关联在确定铁磷属元素超导体的电子结构中的重要性。
英文摘要：
We report on a band structure calculation and de Haas-van Alphen measurements of KFe$_2$As$_2$. Three cylindrical Fermi surfaces are found. Effective masses of electrons range from 6 to 18$m_e$, $m_e$ being the free electron mass. Remarkable discrepancies between the calculated and observed Fermi surface areas and the large mass enhancement ($\gtrsim 3$) highlight the importance of electronic correlations in determining the electronic structures of iron pnicitide superconductors.
Fermi surface in KFe2As2 determined via de Haas-van Alphen oscillation measurements
我们用de Haas-van Alphen（dHvA）方法完全确定了KFe $_2$ As $_2$的费米面。在KFe $_2$ As $_2$中观察到基频$ε$、$α$、$ζ$和$β$。第一个是由于孔柱附近的布里渊区的X点，而其他的孔柱在$Γ$点。我们还观察到$α$和$ζ$之间的磁击穿频率，并提出了一个合理的解释。实验频率显示偏离带结构计算预测的频率。已经发现$B \parallel c$的有效质量高达19 $m_e$，$m_e$是自由电子质量。计算得到的载流子数和索末菲系数分别为1.01 - 1.03个空穴/分子式单元和82 - 94 mJmol $^{-1}$ K $^{-2}$，与化学计量和直接测量值93 mJmol $^{-1}$ K $^{-2}$一致[H.泽\textit{et al} .，日本物理学会\textbf{80SA}，SA 118（2011）]。索末菲系数在带值上增强了约9倍，表明低能自旋和/或轨道波动的重要性，并将KFe $_2$ As $_2$置于强相关金属中。我们还对Ba $_{0.07}$ K $_{0.93}$ Fe $_2$ As $_2$进行了dHvA测量，并观察了$α$和$β$频率。
Superconducting Fluctuations and the Reduced Dimensionality of the Organic Superconductor $κ$- (BEDT-TTF)$_{2}$Cu(NCS)$_{2}$ as Observed through Measurements of the de Haas-van Alphen Effect
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。
Multiple Quantum Oscillations in the de Haas van Alphen Spectra of the Underdoped High Temperature Superconductor YBa_2Cu_3O_6.5
通过改进实验条件和大量的数据积累，我们对欠掺杂高温超导体$_{2}$ O $_{3}$的de Haas-van Alphen效应的测量取得了很高的精度。我们发现，主振荡，到目前为止被认为是单频，是由三个紧密间隔的频率。我们把这归因于双层分裂和一个单一的准二维费米面的翘曲，表明\emph{c}轴的相干性恢复在低温下在欠掺杂的铜氧化物。我们的结果不支持最近报道的在同一化合物中存在1650 T量级的更大频率[S. E. Sebastian { \it等人}，Nature { \bf 454}，200（2008）]。
Comment on Multiple Quantum Oscillations in the de Haas - van Alphen Spectra of the Underdoped High-Temperature Superconductor YBa2Cu3O6.5 (A. Audouard et al., Phys. Rev. Lett. 103 (2009) 157003)
A de Haas-van Alphen study of the filled skutterudite compounds PrOs$_4$As$_{12}$ and LaOs$_4$As$_{12}$
在高达40 T的磁场下，对填充方钴矿PrOs $_4$ As $_{12}$和LaOs $_4$ As $_{12}$单晶的磁化率和de Haas-van Alphen效应随磁场方向的变化进行了全面的研究。几个峰值中观察到的低场磁化率的PrOs $_4$作为$_{12}$，对应于级联的变磁性转变分离的低场反铁磁和高场顺磁金属（PMM）相。de Haas-van Alphen实验表明，PMM相的PrOs $_4$ As $_{12}$和LaOs $_4$ As $_{12}$的费米面拓扑结构非常相似.此外，它们与LaOs $_4$ As $_{12}$在PrOs $_4$ As $_{12}$晶格上的能带结构计算的预测也有合理的一致性.这两个观察结果表明，Pr 4 $f$电子的PMM阶段的巡回准粒子的数量贡献不大。然而，虽然LaOs $_4$ As $_{12}$的性质表明一个传统的超导费米液体，直接交换和电子相关的影响被检测到的PMM相的PrOs $_4$ As $_{12}$。例如，准粒子的有效质量在PrOs $_4$作为$_{12}$被发现减少与增加的领域，可能反映了逐渐抑制与接近的低温，低场反铁磁状态的磁波动。
We have performed de Haas-van Alphen (dHvA) measurements of the heavy-fermion superconductor CeCoIn$_5$ down to 2 mK above the upper critical field. We find that the dHvA amplitudes show an anomalous suppression, concomitantly with a shift of the dHvA frequency, below the transition temperature $T_{\rm n}=20$ mK. We suggest that the change is owing to magnetic breakdown caused by a field-induced antiferromagnetic (AFM) state emerging below $T_{\rm n}$, revealing the origin of the field-induced quantum critical point (QCP) in CeCoIn$_5$. The field dependence of $T_{\rm n}$ is found to be very w…
Fermi surface of SrFe$_2$P$_2$ determined by de Haas-van Alphen effect
本文报道了用de Haas-van Alphen效应测量三元磷化物SrFe $_2$ P $_2$的费米面。该化合物的FS与高温超导体的母体化合物SrFe $_2$ As $_2$非常相似。我们的数据表明费米面是由两个电子和两个空穴层组成的，与能带结构的计算结果一致。几个表显示强烈的c轴翘曲强调三维的重要性，在非磁性状态的三元磷属元素。我们发现电子和空穴袋具有不同的拓扑结构，这意味着这种材料不满足嵌套条件。
We report the first observation of the de Haas-van Alphen (dHvA) effect in the novel spin-triplet superconductor UTe2 using high quality single crystals with the high residual resistivity ratio (RRR) over 200. The dHvA frequencies, named alpha and beta, are detected for the field directions between c and a-axes. The frequency of branch beta increases rapidly with the field angle tilted from c to a-axis, while branch alpha splits, owing to the maximal and minimal cross-sectional areas from the same Fermi surface. Both dHvA branches, alpha and beta reveal two kinds of cylindrical Fermi surfaces …
In the search of topological superconductors, nailing down the Fermiology of the normal state is as crucial a prerequisite as unraveling the superconducting pairing symmetry. In particular, the number of time-reversal-invariant momenta in the Brillouin zone enclosed by Fermi surfaces is closely linked to the topological class of time-reversal-invariant systems, and can experimentally be investigated. We report here a detailed study of de Haas van Alphen quantum oscillations in single crystals of the topological semimetal CaSn$_{3}$ with torque magnetometry in high magnetic fields up to 35 T. I…
We report herein the nontrivial topological states in an intrinsic type-II superconductor BaSn5 (Tc ~ 4.4 K) probed via measuring the magnetizations, specific heat, de Haas-van Alphen (dHvA) effect and performing first principles calculations. The first principles calculations reveal a topological nodal ring structure centering at the H point in the kz = π plane of the Brillouin zone (BZ), which could be gapped by spin-orbit coupling (SOC), yielding rather small gaps below and above the Fermi level about 0.04 eV and 0.14 eV, respectively. The SOC also results in a pair of Dirac points along th…
The negative-U impurity stripes confining the edge channels of semiconductor quantum wells are shown to allow the effective cooling inside in the process of the spin-dependent transport. The aforesaid promotes also the creation of composite bosons and fermions by the capture of single magnetic flux quanta on the edge channels under the conditions of low sheet density of carriers, thus opening new opportunities for the registration of the quantum kinetic phenomena in weak magnetic fields at high temperatures up to the room temperature. As a certain version noted above we present the first findi…
Orbital-dependent electron correlation effect on the two- and three-dimensional Fermi surfaces in KFe2As2 revealed by angle-resolved photoemission spectroscopy
Cyclotron resonance and mass enhancement by electron correlation in KFe$_2$As$_2$
对铁基超导体KFe $_2$ As $_2$进行了回旋共振（CR）测量。观察到CR的一个信号，并且归因于在$Γ$点处的二维$α$费米表面。我们发现CR的有效质量[（3.4 $\pm$ 0.05）$m_e$（$m_e$是自由电子质量）]和de-Haas van Alphen（dHvA）结果存在很大差异，这是由于电子相关导致质量增强的直接证据。CR和dHvA结果的比较表明，带内和带间电子相关有助于在KFe $_2$ As $_2$的质量增强。
Small and nearly isotropic hole-like Fermi surfaces in LiFeAs detected through de Haas van Alphen-effect
LiFeAs是砷基铁磷族化合物超导体中唯一一种不具有磁有序性的近化学计量比化合物。这与电子结构计算不一致，电子结构计算和一个非常稳定的磁性状态，并预测圆柱形的空穴和电子状费米表面片，其几何形状表明自旋波动和嵌套矢量处可能的长程有序不稳定性。事实上，一个复杂的磁性相图中确实观察到的同构NaFeAs化合物。先前的角分辨光电发射（ARPES）实验揭示了空穴和类电子表面的存在，但具有相当不同的横截面积，并且没有嵌套，这被认为是支撑超导体的pnictide家族中的磁序和超导性。这些ARPES观测结果受到了随后的de Haas van Alphen（dHvA）测量的挑战，该测量检测到了一些与原始能带计算大致一致的电子状费米表面片。在这里，我们展示了一个详细的dHvA研究揭示了额外的，小的和几乎各向同性的费米表面片在LiFeAs单晶，这应该对应于孔状轨道，如先前观察到的ARPES。因此，我们的研究结果调和了ARPES和以前的dHvA结果之间的明显差异。这些费米表面口袋的小尺寸表明在LiFeAs的电子相关性的突出作用。间隙节点的情况下，结合准二维和三维费米表面的共存，有利于LiFeAs的s波配对对称性。但是LiFeAs和LiFeP之间类似的类电子费米面结合非常不同的空穴袋，表明LiFeP的能隙函数中的节点可能位于空穴袋上。
According to the celebrated Onsagar-Lifshitz paradigm, the observation of Shubnikov de-Haas and de-Haas van Alphen (SdHvA) oscillations is an indication of the presence of `closed' orbit Fermi surface in the bulk. We present a real-space based calculation of SdHvA oscillations in generalized quasi-one-dimensional lattices by relaxing the quasi-classical approximations embedded in this decades old Onsagar-Lifshitz paradigm. We find that sizable quantum oscillation can arise from `open' Fermi surfaces as long as cyclotron orbits can form in real-space with finite, but not necessarily equal, elec…
