Comment on "Multiple Quantum Oscillations in the de Haas-van Alphen Spectra of the Underdoped High-Temperature Superconductor YBa2Cu3O6.5"

de Haas-van Alphen oscillations in the underdoped cuprate YBa$_2$Cu$_3$O$_{6.5}$

The de Haas-van Alphen effect was observed in the underdoped cuprate YBa$_2$Cu$_3$O$_{6.5}$ via a torque technique in pulsed magnetic fields up to 59 T. Above an irreversibility field of $\sim$30 T, the magnetization exhibits clear quantum oscillations with a single frequency of 540 T and a cyclotron mass of 1.76 times the free electron mass, in excellent agreement with previously observed Shubnikov-de Haas oscillations. The oscillations obey the standard Lifshitz-Kosevich formula of Fermi-liquid theory. This thermodynamic observation of quantum oscillations confirms the existence of a well-de…

Fermi surface and mass enhancement in KFe$_2$As$_2$ from de Haas-van Alphen effect measurements

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.

Phase transition into superconducting mixed state and de Haas - van Alphen effect

The Landau expansion for the free energy of the superconducting mixed state near the upper critical field in powers of the square modulus of the order parameter averaged over Abrikosov lattice is derived. The analytical calculations has been carried out in frame of Gor'kov formalism for 3-dimensional isotropic BCS model beyond the limits of quasiclassical approximation, another words with Landau quantization of the quasiparticle energy levels taken into consideration. The derivation is performed at low temperature and high enough but finite crystal's purity. The effect of Pauli paramagnetic te…

Numerical extraction of de Haas - van Alphen frequencies from calculated band energies

A new algorithm for extracting de Haas-van Alphen frequencies and effective masses from calculated band energies is presented. The algorithm creates an interpolated k-space "super cell," which is broken into slices perpendicular to the desired magnetic field direction. Fermi surface orbits are located within each slice, and de Haas-van Alphen frequencies and effective masses are calculated. Orbits are then matched across slices, and extremal orbits determined. This technique has been successful in locating extremal orbits not previously noticed in the complicated topology of existing UPt3 band…

Multiple Quantum Oscillations in the de Haas van Alphen Spectra of the Underdoped High Temperature Superconductor YBa_2Cu_3O_6.5

By improving the experimental conditions and extensive data accumulation, we have achieved very high-precision in the measurements of the de Haas-van Alphen effect in the underdoped high-temperature superconductor YBa$_{2}$Cu$_{3}$O$_{6.5}$. We find that the main oscillation, so far believed to be single-frequency, is composed of three closely spaced frequencies. We attribute this to bilayer splitting and warping of a single quasi-2D Fermi surface, indicating that \emph{c}-axis coherence is restored at low temperature in underdoped cuprates. Our results do not support the existence of a larger…

A de Haas-van Alphen study of the Fermi surfaces of superconducting LiFeP and LiFeAs

We report a de Haas-van Alphen (dHvA) oscillation study of the 111 iron pnictide superconductors LiFeAs with T_c ~18K and LiFeP with T_c~5K. We find that for both compounds the Fermi surface topology is in good agreement with density functional band-structure calculations and shows quasi-nested electron and hole bands. The effective masses generally show significant enhancement, up to ~3 for LiFeP and ~5 for LiFeAs. However, one hole Fermi surface in LiFeP shows a very small enhancement, as compared with its other sheets. This difference probably results from k-dependent coupling to spin fluct…

UTe2中沿c轴方向的de Haas-van Alphen振荡

de Haas-van Alphen Oscillations for the Field Along c-axis in UTe2

本研究在UTe2中沿c轴磁场下进行dHvA实验，发现三个大有效质量的圆柱形费米面频率，并排除高频其他频率，但小口袋费米面仍可能存在。

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)

Recent observations of slow magneto-oscillations in some underdoped cuprate superconductors are one of the most striking discoveries in the field of superconductivity since many probes of underdoped cuprates clearly point to a non Fermi-liquid normal state. We show that a large magnitude and strong magnetic-field dependence of the residual resistance invalidate the conventional interpretation of the magneto-oscillations as a normal-state dHvA effect. We propose that the oscillations are most likely caused by a quantum interference of vortex and crystal lattice modulations of the order paramete…

De Haas-van Alphen oscillations in the charge-density wave compound lanthanum tritelluride (LaTe_3)

De Haas-van Alphen oscillations were measured in lanthanum tritelluride (LaTe_3) to probe the partially gapped Fermi surface resulting from charge density wave (CDW) formation. Three distinct frequencies were observed, one of which can be correlated with a FS sheet that is unaltered by CDW formation. The other two frequencies arise from FS sheets that have been reconstructed in the CDW state.

Probing the Fermi Surface of 3D Dirac Semimetal Cd$_{3}$As$_{2}$ through de Haas-van Alphen Technique

We have observed Shubnikov-de Haas and de Haas-van Alphen effect in the single crystals of three dimensional Dirac semimetal Cd$_{3}$As$_{2}$ upto 50 K, traceable at field as low as 2 T and 1 T, respectively. The values of Fermi wave vector, Fermi velocity, and effective cyclotron mass of charge carrier, calculated from both the techniques, are close to each other and match well with the earlier reports. However, the de Haas-van Alphen effect clearly reflects the existence of two different Fermi surface cross-sections along certain direction and a non-trivial Berry's phase which is the signatu…

A de Haas-van Alphen study of the filled skutterudite compounds PrOs$_4$As$_{12}$ and LaOs$_4$As$_{12}$

Comprehensive magnetic-field-orientation dependent studies of the susceptibility and de Haas-van Alphen effect have been carried out on single crystals of the filled skutterudites PrOs$_4$As$_{12}$ and LaOs$_4$As$_{12}$ using magnetic fields of up to 40~T. Several peaks are observed in the low-field susceptibility of PrOs$_4$As$_{12}$, corresponding to cascades of metamagnetic transitions separating the low-field antiferromagnetic and high-field paramagnetic metal (PMM) phases. The de Haas-van Alphen experiments show that the Fermi-surface topologies of PrOs$_4$As$_{12}$ in its PMM phase and L…

de Haas-van Alphen oscillations with non-parabolic dispersions

de Haas-van Alphen oscillation spectrum of two-dimensional systems is studied for general power law energy dispersion, yielding a Fermi surface area of the form $S(E)\propto E^α$ for a given energy $E$. The case $α=1$ stands for the parabolic energy dispersion. It is demonstrated that the periodicity of the magnetic oscillations in inverse field can depend notably on the temperature. We evaluated analytically the Fourier spectrum of these oscillations to evidence the frequency shift and smearing of the main peak structure as the temperature increases.

Anomalous change in the de Haas-van Alphen oscillations of CeCoIn$_5$ at ultra-low temperatures

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…

The de Haas-van Alphen effect in Kondo systems with crystalline electric field

The effective mass probed by the de Haas-van Alphen oscillations is studied for a model Ce system under magnetic field higher than the Kondo energy. In the mean-field theory, the mass enhancement per Ce ion in the periodic system is identical with that in the dilute system. With decreasing magnetic field, the effective mass tends to diverge corresponding to a formation of the Kondo ground state. The effective mass can be very different between up and down spins depending on the nature of the 4f wave functions.

Calculated de Haas-van Alphen quantities of Ce(M)In5 (M=Co, Rh, and Ir) compounds

We report a critical analysis of the electronic structures and de Haas-van Alphen (dHvA) quantities of the heavy-fermion superconductors CeCoIn$_5$, CeRhIn$_5$, and CeIrIn$_5$. The electronic structures are investigated {\it ab initio} on the basis of full-potential band-structure calculations, adopting both the scalar- and fully relativistic formulations within the framework of the local spin-density approximation (LSDA). In contrast to another recent study, in which a pronounced change of the Fermi surface due to relativistic effects and therefore the importance of relativistic interactions …

High-Field de Haas-van Alphen Effect in non-centrosymmetric CeCoGe3 and LaCoGe3

We report on de Haas-van Alphen effect measurements in the non-centrosymmetric systems CeCoGe3 and LaCoGe3 in magnetic field up to 28 Tesla. In both compounds, two new high frequencies were observed in high fields. The frequencies were not detected in previous lower field measurements. The frequencies do not originate from magnetic breakdown, and, therefore, are likely to be intrinsic features of the compounds. In CeCoGe3, the corresponding effective masses are strongly enhanced, being of the order of 30 bare electron masses.

The de Haas-van Alphen effect across the metamagnetic transition in Sr$_3$Ru$_2$O$_7$

We report a study of the de Haas-van Alphen (dHvA) effect on the itinerant metamagnet Sr$_3$Ru$_2$O$_7$. Extremely high sample purity allows the observation of dHvA oscillations both above and below the metamagnetic transition field of 7.9 T. The quasiparticle masses are fairly large away from the transition, and are enhanced by up to an extra factor of three as the transition is approached, but the Fermi surface topography change is quite small. The results are qualitatively consistent with a field-induced Stoner transition in which the mass enhancement is the result of critical fluctuations.

On the de Haas-van Alphen effect in inhomogeneous alloys

We show that Landau level broadening in alloys occurs naturally as a consequence of random variations in the local quasiparticle density, without the need to consider a relaxation time. This approach predicts Lorentzian-broadened Landau levels similar to those derived by Dingle using the relaxation-time approximation. However, rather than being determined by a finite relaxation time $τ$, the Landau-level widths instead depend directly on the rate at which the de Haas-van Alphen frequency changes with alloy composition. The results are in good agreement with recent data from three very differen…

杂化能隙绝缘体中的 de Haas van Alphen 振荡：作为 Landau 能级抗磁矩的突变

de Haas van Alphen oscillations in hybridization-gap insulators as a sudden change in the diamagnetic moment of Landau levels

该研究重新分析杂化能隙绝缘体的量子振荡半经典理论，指出 T=0 K 时振荡源于 Landau 能级穿越价带杂化区域引发的抗磁矩突变。

重费米子SmB$_6$化合物中的德哈斯-范阿尔芬效应与巨温度峰

De Haas-van Alphen effect and a giant temperature peak in heavy fermion SmB$_6$ compound

本文提出理论模型解释绝缘SmB$_6$中极低温下德哈斯-范阿尔芬振荡振幅的巨温度峰，指出由两种不同质量费米子杂化产生的重费米子杂化态是峰的成因，并探讨其边缘态情景。

De Haas-van Alphen oscillations in the compensated organic metal alpha-'pseudo-kappa'-(ET)4H3O[Fe(C2O4)3].(C6H4Br2)

Field-, temperature- and angle-dependent Fourier amplitude of de Haas-van Alphen (dHvA) oscillations are calculated for compensated two-dimensional (2D) metals with textbook Fermi surface (FS) composed of one hole and two electron orbits connected by magnetic breakdown. It is demonstrated that, taking into account the opposite sign of electron and hole orbits, a given Fourier component involves combination of several orbits, the contribution of which must be included in the calculations. Such FS is observed in the strongly 2D organic metal alpha-'pseudo-kappa'-(ET)4H3O[Fe(C2O4)3].(C6H4Br2), dH…

de Haas-van Alphen oscillations for non-relativistic fermions coupled to an emergent U(1) gauge field

We investigate magento-oscillations in the specific heat of non-relativistic fermions with a Fermi surface minimally coupled to a fluctuating U(1) gauge field. Our study is motivated by the recent observation of quantum oscillations in the underdoped cuprates, and by theoretical models of pocket Fermi surfaces realizing a non-Fermi liquid `algebraic charge liquid'. Our main result is the computation of the order 1/N correction to the Lifshitz-Kosevich expression for the oscillation amplitude in the dirty limit in a model with N species of fermions.

New insights on frequency combinations and 'forbidden frequencies' in de Haas-van Alphen spectrum of \k{appa}-(ET) 2 Cu(SCN) 2

De Haas-van Alphen oscillations of the organic metal \k{appa}-(ET) 2 Cu(SCN) 2 have been measured up to 55 T at liquid helium temperatures. The Fermi surface of this charge transfer salt is a textbook example of linear chain of orbits coupled by magnetic breakdown. Accordingly, the oscillation spectrum is composed of linear combinations of the frequencies linked to the $α$ and magnetic breakdown-induced $β$ orbits. The field and temperature dependence of all the observed Fourier components, in particular the "forbidden frequency" $β$ -- $α$ which cannot correspond to a classical orbit, are qua…

Quantum oscillations without a Fermi surface and the anomalous de Haas-van Alphen effect

The de Haas-van Alphen effect (dHvAe), describing oscillations of the magnetization as a function of magnetic field, is commonly assumed to be a definite sign for the presence of a Fermi surface (FS). Indeed, the effect forms the basis of a well-established experimental procedure for accurately measuring FS topology and geometry of metallic systems, with parameters commonly extracted by fitting to the Lifshitz-Kosevich (LK) theory based on Fermi liquid theory. Here we show that, in contrast to this canonical situation, there can be quantum oscillations even for band insulators of certain types…

Magnetotransport and de Haas-van Alphen measurements in the type-II Weyl semimetal TaIrTe$_4$

The layered ternary compound TaIrTe$_4$ has been predicted to be a type-II Weyl semimetal with only four Weyl points just above the Fermi energy. Performing magnetotransport measurements on this material we find that the resistivity does not saturate for fields up to 70 T and follows a $ ρ\sim B^{1.5}$ dependence. Angular-dependent de Haas-van Alphen (dHvA) measurements reveal four distinct frequencies. Analyzing these magnetic quantum oscillations by use of density functional theory (DFT) calculations we establish that in TaIrTe$_4$ the Weyl points are located merely $\sim$ 40-50 meV above th…

Fermi surface in KFe2As2 determined via de Haas-van Alphen oscillation measurements

We have completely determined the Fermi surface in KFe$_2$As$_2$ via de Haas-van Alphen (dHvA) measurements. Fundamental frequencies $ε$, $α$, $ζ$, and $β$ are observed in KFe$_2$As$_2$. The first one is attributed to a hole cylinder near the X point of the Brillouin zone, while the others to hole cylinders at the $Γ$ point. We also observe magnetic breakdown frequencies between $α$ and $ζ$ and suggest a plausible explanation for them. The experimental frequencies show deviations from frequencies predicted by band structure calculations. Large effective masses up to 19 $m_e$ for $B \parallel c…

Split Fermi Surfaces of the Spin-Orbit-Coupled Metal Cd2Re2O7 Probed by de Haas-van Alphen Effect

The superconducting pyrochlore oxide Cd2Re2O7 shows a structural transition with inversion symmetry breaking (ISB) at Ts1 = 200 K. A recent theory [L. Fu, Phys. Rev. Lett. 115, 026401 (2015)] suggests that the origin is an electronic instability that leads to a multipolar order in the spin-orbit-coupled metal. To observe the Fermi surface of the low-temperature phase of Cd2Re2O7, we perform de Haas-van Alphen effect measurements by means of magnetic torque. In reference to a calculated band structure, the spin-split Fermi surfaces with large cyclotron masses of 5-9m0 are revealed. The splittin…

de Haas-van Alphen measurement of the antiferromagnet URhIn$_5$

We report on the results of a de Haas-van Alphen (dHvA) measurement performed on the recently discovered antiferromagnet URhIn$_5$ ($T_N$ = 98 K), a 5\textit{f}-analogue of the well studied heavy fermion antiferromagnet CeRhIn$_5$. The Fermi surface is found to consist of four surfaces: a roughly spherical pocket $β$, with $F_β\simeq 0.3$ kT; a pillow-shaped closed surface, $α$, with $F_α\simeq 1.1$ kT; and two higher frequencies $γ_1$ with $F_{γ_1} \simeq 3.2$ kT and $γ_2$ with $F_{γ_2} \simeq 3.5$ kT that are seen only near the \textit{c}-axis, and that may arise on cylindrical Fermi surface…

First Observation of de Haas-van Alphen Effect and Fermi Surfaces in Unconventional Superconductor UTe2

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 …

High Field de Haas - van Alphen Studies of the Fermi Surfaces of LaMIn$_{5}$ (M = Co, Rh, Ir)

We report measurements of the de Haas - van Alphen effect on a series of compounds, LaMIn$_{5}$ (M = Co, Rh, Ir). The results show that each of the Co and Ir Fermi surfaces (FSs) exhibit some portions that are two dimensional and some portions that are three dimensional. The most two dimensional character is exhibited in LaCoIn$_{5}$, less two dimensional behavior is seen in LaIrIn$_{5}$, no part of Fermi surface of LaRhIn$_{5}$ is found to have a two dimensional character. Thus the two dimensionality of portions of the FSs is largely determined by the d character of the energy bands while all…

A de Haas van Alphen study of the role of 4f electrons in antiferromagnetic CeZn11 as compared to its non-magnetic analogue LaZn11

We present a de Haas-van Alphen study of the Fermi surface of the low temperature antiferromagnet CeZn11 and its non-magnetic analogue LaZn11, measured by torque magnetometry up to fields of 33T and at temperatures down to 320 mK. Both systems possess similar de Haas-van Alphen frequencies, with three clear sets of features - ranging from 50T to 4kT - corresponding to three bands of a complex Fermi surface, with an expected fourth band also seen weakly in CeZn11. The effective masses of the charge carriers are very light (<1 me) in LaZn11 but a factor of 2 - 4 larger in CeZn11, indicative of s…

Exotic Heavy Fermion State in the Filled Skutterudite PrFe$_4$P$_{12}$ Uncovered by the de Haas-van Alphen Effect

We report the de Haas-van Alphen (dHvA) experiment on the filled skutterudite PrFe$_4$P$_{12}$ exhibiting apparent Kondo-like behaviors in the transport and thermal properties. We have found enormously enhanced cyclotron effective mass $m^{\rm \ast}_{\rm c}=81 m_{\rm 0}$ in the high field phase (HFP), which indicates that PrFe$_4$P$_{12}$ is the first Pr-compound in which really heavy mass has been unambiguously confirmed. Also in the low field non-magnetic ordered phase (LOP), we observed the dHvA branch with $m^{\rm \ast}_{\rm c}=10 m_{0}$ that is quite heavy taking into account its small Fe…

Electronic structure and de Haas-van Alphen frequencies in KFe2As2 within LDA+DMFT

Recent density functional theory (DFT) calculations for KFe2As2 have shown to be insufficient to satisfactorily describe angle-resolved photoemission (ARPES) measurements as well as observed de Haas van Alphen (dHvA) frequencies. In the present work, we extend DFT calculations based on the full-potential linear augmented plane-wave method by dynamical mean field theory (DFT+DMFT) to include correlation effects beyond the local density approximation. Our results indicate that KFe2As2 is a moderately correlated metal with a mass renormalization factor of the Fe 3d orbitals between 1.6 and 2.7. A…

The Anomalous de Haas-van Alphen Effect in InAs/GaSb quantum wells

The de Haas-van Alphen effect (dHvAe) describes the periodic oscillation of the magnetisation in a material as a function of inverse applied magnetic field. It forms the basis of a well established procedure for measuring Fermi surface properties and its observation is typically taken as a direct signature of a system being metallic. However, certain insulators can show similar oscillations of the magnetisation from quantisation of the energies of electron states in filled bands. Recently the theory of such an ${\it anomalous}$ dHvAe (AdHvAe) has been worked out but so far there is no clear ex…

Three-dimensional topological semimetal phase in layered TaNiTe5 probed by de Haas-van Alphen effect

Layered three-dimensional (3D) topological semimetals have attracted intensively attention due to the exotic phenomena and abundantly tunable properties. Here we report the experimental evidence for the 3D topological semimetal phase in layered material TaNiTe5 single crystals through quantum oscillations. Strong quantum oscillations have been observed with diamagnetism background in TaNiTe5. By analyzing the de Haas-van Alphen oscillations, multi-periodic oscillations were extracted, in content with magnetotransport measurements. Moreover, nontrivial "π" Berry phase with 3D Fermi surface is i…

Fermi surface evolution through a heavy fermion superconductor-to-antiferromagnet transition: de Haas-van Alphen effect in Cd-substituted CeCoIn$_5$

We report the results of de-Haas-van-Alphen (dHvA) measurements in Cd doped CeCoIn$_5$ and LaCoIn$_5$. Cd doping is known to induce an antiferromagnetic order in the heavy fermion superconductor CeCoIn$_5$, whose effect can be reversed with applied pressure. We find a slight but systematic change of the dHvA frequencies with Cd doping in both compounds, reflecting the chemical potential shift due to the addition of holes. The frequencies and effective masses are close to those found in the nominally pure compounds with similar changes apparent in the Ce and La compounds with Cd substitution. W…

通过德哈斯-范阿尔芬振荡揭示的CsV$_{3}$Sb$_{5}$的基态晶格畸变

The Ground State Lattice Distortion of CsV$_{3}$Sb$_{5}$ Revealed by de Haas-van Alphen Oscillations

本研究结合扭矩磁强计与密度泛函理论，通过德哈斯-范阿尔芬振荡研究CsV₃Sb₅的费米面，发现CDW序中SoD和TrH两种2×2×2畸变模式共存，为理解其电子维度、CDW与超导的相互作用提供关键依据。

De Haas-van Alphen effect and Fermi surface properties of single crystal CrB2

We report the angular dependence of three distinct de Haas-van Alphen (dHvA) frequencies of the torque magnetization in the itinerant antiferromagnet CrB2 at temperatures down to 0.3K and magnetic fields up to 14T. Comparison with the calculated Fermi surface of nonmagnetic CrB2 suggests that two of the observed dHvA oscillations arise from electron-like Fermi surface sheets formed by bands with strong B-px,y character which should be rather insensitive to exchange splitting. The measured effective masses of these Fermi surface sheets display strong enhancements of up to a factor of two over t…

关联绝缘体中随温度变化的 de Haas-van Alphen 效应与量子振荡

De Haas-van Alphen effect and quantum oscillations as a function of temperature in correlated insulators

研究激子绝缘体模型中由Coulomb相互作用驱动的能带杂化，发现杂化能隙随磁场减小且de Haas-van Alphen振荡振幅随温度倒数周期变化，并解析求得主峰位置与高度。

多体相互作用对绝缘体中德哈斯-范阿尔芬振荡的影响

Effect of many-body interaction on de Haas-van Alphen oscillations in insulators

本研究针对窄能隙反转能带绝缘体中出现的非常规dHvA振荡，建立理论研究弱多体相互作用下准粒子谱重整化的影响，发现特定区间内弱相互作用可显著增强振荡振幅。

笼目金属RbTi3Bi5中的德哈斯-范阿尔芬量子振荡

The de Haas-van Alphen quantum oscillations in the kagome metal RbTi3Bi5

本文通过dHvA振荡测量与理论计算研究笼目金属RbTi3Bi5，揭示其二维费米口袋β具有轻有效质量和零贝里相位，表明该材料是探索非平庸拓扑态的良好候选体系。

利用温度调制的回旋质量选择性 de Haas-van Alphen 测量

Cyclotron mass-selective de Haas-van Alphen measurements using temperature modulation

提出一种温度调制的 de Haas-van Alphen 测量技术，通过非单调振幅演化选择性探测不同有效质量的量子振荡，并实验验证其在 MoSi2 中分离重轨道弱信号的能力。

三维边际费米液体的熵与德哈斯-范阿尔芬振荡

Entropy and de Haas-van Alphen oscillations of a three-dimensional marginal Fermi liquid

本研究针对三维量子临界边际费米液体的德哈斯-范阿尔芬振荡，指出传统Lifshitz-Kosevich扩展方法在关联长度超回旋半径时失效，通过Luttinger-Ward-Eliashberg框架纳入相关效应，得到非费米区仍有效的熵与磁化振荡修正式。

Anisotropic transport and de Haas$-$van Alphen oscillations in quasi-one-dimensional TaPtTe$_5$

Because of the unique physical properties and potential applications, the exploration of quantum materials with diverse symmetry-protected topological states has attracted considerable interest in the condensed-matter community in recent years. Most of the topologically nontirvial materials identified thus far have two-dimensional or three-dimensional structural characteristics, while the quasi-one-dimensional (quasi-1D) analogs are rare. Here we report on anisotropic magnetoresistance, Hall effect, and quantum de Haas$-$van Alphen (dHvA) oscillations in TaPtTe$_5$ single crystals, which posse…

反铁磁体 U$_2$RhIn$_8$ 的准二维费米面由 de Haas-van Alphen 测量揭示

Quasi-two-dimensional Fermi surfaces of the antiferromagnet U$_2$RhIn$_8$ revealed by de Haas-van Alphen measurements

通过测量反铁磁重费米子化合物 U$_2$RhIn$_8$ 的霍尔效应和 dHvA 效应，发现反铁磁相中载流子密度降低且存在三个准二维费米面，结合能带计算验证了反铁磁基态下的二维费米面特征。

On the de Haas - van Alphen oscillations in quasi-two-dimensional metals: effect of the Fermi surface curvature

Here, we present the results of theoretical analysis of the de Haas-van Alphen oscillations in quasi-two-dimensional normal metals. We had been studying effects of the Fermi surface (FS) shape on these oscillations. It was shown that the effects could be revealed and well pronounced when the FS curvature becomes zero at cross-sections with extremal cross-sectional areas. In this case both shape and amplitude of the oscillations could be significantly changed. Also, we analyze the effect of the FS local geometry on the angular dependencies of the oscillation amplitudes when the magnetic field i…

de Haas-van Alphen效应揭示Kagome金属FeGe电荷密度波态中展开费米面的证据

Evidence for Unfolded Fermi Surfaces in the Charge-Density-Wave State of Kagome Metal FeGe Revealed by de Haas-van Alphen Effect

本研究利用最高45.2 T磁场下的de Haas-van Alphen效应测量并结合能带计算，揭示FeGe的CDW态中存在对CDW重构稳健的展开费米面特征。

Fermi surface of MoO2 studied by angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations

A comprehensive study of the electronic properties of monoclinic MoO2 from both an experimental and a theoretical point of view is presented. We focus on the investigation of the Fermi body and the band structure using angle resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations. For the latter, the new full-potential augmented spherical wave (ASW) method has been applied. Very good agreement between the experimental and theoretical results is found. In particular, all Fermi surface sheets are correctly identified by all three approaches. Pr…

Localized f electrons in CexLa1-xRhIn5: dHvA Measurements

Measurements of the de Haas-van Alphen effect in CexLa1-xRhIn5 reveal that the Ce 4f electrons remain localized for all x, with the mass enhancement and progressive loss of one spin from the de Haas-van Alphen signal resulting from spin fluctuation effects. This behavior may be typical of antiferromagnetic heavy fermion compounds, inspite of the fact that the 4f electron localization in CeRhIn5 is driven, in part, by a spin-density wave instability.

The de Haas van Alphen effect near a quantum critical end point in Sr_3Ru_2O_7

Highly correlated electron materials are systems in which many new states of matter can emerge. A particular situation which favours the formation of exotic phases of the electron liquid in complex materials is that where a quantum critical point (QCP) is present the phase diagram. Neighbouring regions in parameter space reveal unusual physical properties, described as non-Fermi liquid behaviour. One of the important problems in quantum criticality is to find out how the Fermi surface (FS) of a material evolves near a QCP. The traditional method for studying the FS of materials is the de Haas …

Fermi surfaces and quantum oscillations in underdoped high-Tc superconductors YBa2Cu3O6.5 and YBa2Cu4O8

We study underdoped high-Tc superconductors YBa2Cu3O6.5 and YBa2Cu4O8 using first-principles pseudopotential methods with additional Coulomb interactions at the Cu atoms, and obtain Fermi-surface pocket areas in close agreement with measured Shubnikov-de Haas and de Haas-van Alphen oscillations. With antiferromagnetic order in CuO2 planes, stable in the calculations, small hole pockets are formed near the so-called Fermi-arc positions in the Brillouin zone which reproduce the low-frequency oscillations. A large electron pocket, necessary for the negative Hall coefficient, is also formed in YBa…

费米液体中 de Haas-van Alphen 量子振荡的玻色化理论

Bosonized theory of de Haas-van Alphen quantum oscillation in Fermi liquids

本文通过费米面的伴随轨道玻色化解决了 2d 费米液体中自能振荡导致的 de Haas-van Alphen 效应难题，将问题简化为 0+1D 量子力学，并推导出偏离 Lifshitz-Kosevich 公式的解析表达式。

通过 de Haas-van Alphen 量子振荡探测 IrO$_2$ 的费米面和有效质量

Fermi surface and effective masses of IrO$_2$ probed by de Haas-van Alphen quantum oscillations

本研究结合 de Haas-van Alphen 量子振荡测量与 DFT 能带计算，确定了 IrO$_2$ 的费米面拓扑及其增强的载流子有效质量，并与 Dirac 节线相关材料进行对比。

Quantum oscillations in underdoped YBa_2Cu_3O_6.5

Shubnikov-de Haas and de Haas-van Alphen effects have been measured in the underdoped high temperature superconductor YBa$_2$Cu$_3$O$_{6.51}$. Data are in agreement with the standard Lifshitz-Kosevitch theory, which confirms the presence of a coherent Fermi surface in the ground state of underdoped cuprates. A low frequency $F = 530 \pm 10$ T is reported in both measurements, pointing to small Fermi pocket, which corresponds to 2% of the first Brillouin zone area only. This low value is in sharp contrast with that of overdoped Tl$_2$Ba$_2$CuO$_{6+δ}$, where a high frequency $F = 18$ kT has bee…