We investigate the effect of a dynamical collective mode coupled with quasiparticles at specific wavevectors only. This coupling describes the incipient tendency to order and produces shadow spectral features at high energies, while leaving essentially untouched the low energy quasiparticles. This allows to interpret seemingly contradictory experiments on underdoped cuprates, where many converging evidences indicate the presence of charge (stripe or checkerboard) order, which remains instead elusive in the Fermi surface obtained from angle-resolved photoemission experiments.
We report a polarization-resolved Raman spectroscopy study of the orbital dependence of the quasiparticles properties in the prototypical multi-band Fermi liquid Sr\textsubscript{2}RuO\textsubscript{4}. We show that the quasiparticle scattering rate displays $ω^{2}$ dependence as expected for a Fermi liquid. Besides, we observe a clear polarization-dependence in the energy and temperature dependence of the quasiparticle scattering rate and mass, with the $d_{xz/yz}$ orbital derived quasiparticles showing significantly more robust Fermi liquid properties than the $d_{xy}$ orbital derived ones. …
Electron-Hole Scattering Dichotomy and Anisotropic Warping in Quasi-Two-Dimensional Fermi Surfaces of UTe2
Advanced Science Research Center, Japan Atomic Energy Agency（日本原子力机构先进科学研究中心）；Faculty of Engineering, Niigata University（新潟大学工学部）；Institute of Solid State and Materials Physics, Dresden University of Technology（德累斯顿工业大学固体与材料物理研究所）；Helmholtz-Zentrum Dresden-Rossendorf（亥姆霍兹德累斯顿-罗斯多夫中心）；Institute for Solid State Physics (ISSP), University of Tokyo（东京大学固体物理学研究所）；Institute for Materials Research, Tohoku University（东北大学物质材料研究所学）；Max Planck Institute for Chemical Physics of Solids（马克斯·普朗克固体化学物理学研究所）；Department of Physics, Graduate School of Science, Kyoto University（京都大学理学研究科物理学系）
Fermi Surface Properties, Metamgnetic Transition and Quantum Phase Transition of CeRu$_2$Si$_2$ and Its Alloys Probed by the dHvA Effect--Fermi Surface Studies on the Itinerant and Localized Dichotomy of $f$ Electron Nature
本文用deHaas-van Alphen（dHvA）效应研究了CeRu $_2$ Si $_2$及其合金体系CeRu $_2$（Si $_x$ Ge $_{1-x}$）$_2$和CePDMATHABMN La $_{1-x}$ Ru $_2$ Si $_2$的费米面性质.我们特别关注费米面性质和f电子态是如何随磁性而变化的，特别是它们是如何与变磁跃迁和量子相变联系起来的。在总结了CeRu $_2$ Si $_2$的重要物理性质之后，我们给出了CeRu $_2$（Si $_x$ Ge $_{1-x}$）$_2$和Ce $_x$ La $_{1-x}$ Ru $_2$ Si $_2$作为温度、磁场和浓度$x$的函数的磁相图。从磁相图的特征出发，我们认为除了反铁磁相互作用和近藤效应外，铁磁相互作用也是决定磁性的主要因素，并且这些系统中的变磁相变与铁磁相互作用有关.我们总结了费米表面性能的CeRu $_2$ Si $_2$在磁场下的变磁转变的f电子状态现在是很好地理解的理论和实验。本文给出了CeRu $_2$（Si $_x$ Ge $_{1-x}$）$_2$和CePDMATHABMN La $_{1-x}$ Ru $_2$ Si $_2$以及CeRu $_2$ Si $_2$在变磁跃迁以上磁场的实验结果，表明变磁跃迁以上的费米表面性质与变磁跃迁以下的费米表面性质在许多重要方面有显著的不同.…
Geometric orthogonal metals: Hidden antiferromagnetism and pseudogap from fluctuating stripes
Ludwig-Maximilians-Universität München（慕尼黑大学）；Arnold Sommerfeld Center for Theoretical Physics (ASC)（阿诺德·索末菲理论物理中心）；Munich Center for Quantum Science and Technology (MCQST)（慕尼黑量子科学与技术中心）；University of Regensburg（雷根斯堡大学）
The interplay of phase fluctuations and nodal quasiparticles: ubiquitous Fermi arcs in two-dimensional d-wave superconductors
State Key Laboratory of Surface Physics, Fudan University（复旦大学表面物理国家重点实验室）；Center for Field Theory and Particle Physics, Department of Physics, Fudan University（复旦大学物理系场论与粒子物理中心）；Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院人工结构及量子控制教育部重点实验室）；Hefei National Laboratory（合肥国家实验室）
In quantum materials, electrons that have strong correlations tend to localize, leading to quantum spins as the building blocks for low-energy physics. When strongly correlated electrons coexist with more weakly-correlated conduction electrons, multiple channels of effective interactions develop and compete with each other. The competition creates quantum fluctuations having a large spectral weight, with the associated entropies reaching significant fractions of $R\ln 2$ per electron. Advancing a framework to understand how the fluctuating local moments influence unconventional superconductivi…
We report the first comprehensive microscopic description of the thermal fluctuations tuned Fermi surface characteristics in a non-centrosymmetric superconductor, in presence of an in-plane Zeeman field. Using a non perturbative approach we demonstrate that short range fluctuating superconducting pair correlations give rise to segmentation of the Fermi surface with direction dependent pair breaking and hotspots for quasiparticle scattering. Further, a fluctuation driven change in the Fermi surface topology is realized, characterized by a shift of the corresponding Dirac point from the trivial …
The quest to understand the nature of the electronic state in SmB6 has been challenging, perplexing and surprising researchers for over half a century. In the theoretically predicted topological Kondo insulator SmB6, the nature of the bulk electronic structure is not characterised unambiguously by quantum oscillations due to contrary interpretations. One simple definition of an electrical insulator is a material that lacks a Fermi surface and here we report the results of our investigation into its existence in SmB6 by Compton scattering. Compton scattering measures occupied electron momentum …
We theoretically explore 2d moiré heterostructures in lattice-commensurate magnetic fields as platforms for quantum simulation of a paradigmatic model of non-Fermi liquid physics: a Fermi-surface coupled to a fluctuating gauge field. In these moiré-Hofstadter (MH) systems, long-wavelength acoustic phonons exhibit singular interactions with electrons analogous to those of electrons with 2d gauge fields. This leads to a breakdown of Fermi-liquid theory at low temperatures. We show that a combination of large moiré-unit cell size, tunable Fermi-surface topology, and enhanced coupling to interlaye…
We study a distinct type of non-Fermi liquid where there exists an infinite number of critical bosonic modes instead of a finite number of bosonic modes for the conventional ones. We consider itinerant magnets with both conduction electrons and fluctuating magnetic moments in three dimensions. With the Dzyaloshinskii-Moriya interaction, the moments fluctuate near a boson surface in the reciprocal space at low energies when the system approaches an ordering transition. The infinite number of critical modes on the boson surface strongly scatter the gapless electrons on the Fermi surface and conv…
Dynamical phase transition (DPT) characterizes the abrupt change of dynamical properties in nonequilibrium quantum many-body systems. It has been demonstrated that extra quantum fluctuating modes besides the conventional order parameter field can drastically change the properties of equilibrium phase transitions. However, the counterpart phenomena in DPTs have rarely been explored. Here, we study the DPT in the Dirac system after a sudden quench, and find that the fermion fluctuations can round a putative first-order DPT into a dynamical critical point, which is referred to as a fermion-induce…
