Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session M69: Fe-based Superconductors: Strong Electronic CorrelationsFocus Recordings Available
|
Hide Abstracts |
Sponsoring Units: DMP DCMP DCOMP Chair: Laura Fanfarillo, University of Florida/SISSA Room: Hyatt Regency Hotel -Jackson Park A |
Wednesday, March 16, 2022 8:00AM - 8:36AM |
M69.00001: Accurate modeling of iron-based superconductors with screened Fock exchange and Hund metal correlations Invited Speaker: Tommaso Gorni We reproduce the electronic properties of FeSe in the high-temperature phase within an ab initio framework that includes screened Fock exchange and local dynamical correlations. We robustly capture the experimental band structure, as long as the system is in the Hund metal phase. In particular, we account for the shrinking of the Fermi pockets and the sinking below the Fermi level of the hole pocket with xy orbital character. This entails the elusive correct estimate of the Sommerfeld coefficient, and supports the interpretation of noncompensated Fermi pockets seen in ARPES in terms of surface electron doping. More stringently, our modeling matches well the experimental interband optical spectrum, and captures qualitatively the temperature dependence of the thermoelectric power, extremely sensitive to the details of the bands around the Fermi level. |
Wednesday, March 16, 2022 8:36AM - 8:48AM |
M69.00002: Orbital-selective correlations and renormalized electronic structure in LiFeAs Huihang Lin, Rong Yu, Jian-Xin Zhu, Qimiao Si Multiorbital physics is important to both the correlation physics and topological behavior of quantum materials. LiFeAs is a prototype iron pnictide suitable for indepth investigation of this issue. Its electronic structure is strikingly different from the prediction of the noninteracting description. By studying a multiorbital Hubbard model using a U(1) slave spin theory, we demonstrate a new mechanism for a substantial change to the Fermi surface, namely, orbital selectivity of the energy-level renormalization cooperating with its counterpart in quasiparticle spectral weight. Using this effect, we show how the dominating features of the electronic structure in LiFeAs are understood by the local correlations alone. Our results set the stage to understand the origins and nature of both the unconventional superconductivity and likely electronic topology in this prototype iron pnictide and, more generally, reveal a remarkable degree of universality out of the seemingly complex multiorbital building blocks across a broad range of strongly correlated superconductors. |
Wednesday, March 16, 2022 8:48AM - 9:00AM |
M69.00003: Hund excitations in orbital-selective Mott insulators Maksymilian Sroda, Elbio R Dagotto, Jacek Herbrych Multiorbital systems display a variety of novel phenomena originating in the competition between electronic, orbital, and spin degrees of freedom. Prominent among these novel effects is the orbital-selective Mott phase (OSMP), where interactions acting on a multiorbital Fermi surface cause the selective localization of electrons on one of the orbitals. It is believed that such a scenario is realized in the family of low-dimensional iron-based superconductors AFe2X3. In this talk, I will discuss the single-particle spectral function of the OSMP (relevant for ARPES experiments). Especially, I will focus on (i) the effect of the magnetic order present in the system and (ii) the novel band of excitations with the energy inside the Mott gap (of the corresponding single-band Hubbard model). The latter band emerges due to the Hund-exchange splitting of one of the Hubbard bands. Finally, I will discuss the frequency dependence of the optical conductivity. |
Wednesday, March 16, 2022 9:00AM - 9:36AM |
M69.00004: Scaling of the strange-metal scattering in unconventional superconductors Invited Speaker: Kui Jin About one decade ago, several groups [1-3] unveiled an intimated correlation between the superconducting transition temperature (T c ) and the slope of the T-linear resistivity (A 1 ). That is, these two quantities increase or decrease simultaneously. Consequently, the question the community has been after is: what connects the strength of superconductivity with electron scattering? To solve this issue, one needs to quantify the relationship between T c and A 1 . However, it turns out to be a great challenge to manipulate external parameters for marked evolution of properties with minute changes. In this talk, I would like to share with you two pieces of our recent work [4,5] and report on the discovery of T c ~ A 1 0.5 relationship in different families of high-temperature superconductors. For a cuprate system La 2-x Ce x CuO 4 , we developed advanced high-throughput techniques and used a combinatorial library to map how superconducting properties and normal-state properties of the superconductor evolve with minute compositional variation (Δx) with unprecedented resolution and accuracy [4]. We also achieved continuous evolution of superconductivity in ion-gated FeSe film via electric-field gating technique integrated with two-coil mutual inductance and electrical transport property measurements [5]. Such relationship between T c and A 1 is at work for both systems, yet different techniques were employed to tune the superconductivity minutely. Remarkably, the scaling is seemingly satisfied also in hole-doped cuprate, as well as a class of organic superconductors via pressure tuning. This unexpected universal scale indicates that there is perhaps a common origin of superconductivity in unconventional superconductors. |
Wednesday, March 16, 2022 9:36AM - 9:48AM |
M69.00005: High-Field Magnetotransport and Superconductor-Insulator Transition of FeSe Thin Films Max C Stanley, Yanan Li, Fan Zhang, Ross D McDonald, Scott A Crooker, Nitin Samarth The interfacial superconductivity of FeSe on SrTiO3 has been a subject of considerable focus in recent years due to a significantly enhanced critical temperature, compared to bulk FeSe, in the monolayer limit. Here we investigate the temperature dependence of both the in-plane and out-of-plane upper critical fields (Hc2) and the high-field magnetoresistance behavior up to 65 T in few-layer FeSe thin films grown by molecular beam epitaxy on undoped SrTiO3 substrates. This data demonstrates a clear violation of the weak-coupling Pauli limit and provides insight into the pairing mechanisms responsible for high-Tc superconductivity in our FeSe thin films. Additionally, we investigate the carrier density driven superconductor-insulator transition of FeSe by alternating between Fe depositions and both in-situ electronic transport measurements and band structure mappings using angle-resolved photoemission spectroscopy. |
Wednesday, March 16, 2022 9:48AM - 10:00AM |
M69.00006: Flux-flow Hall effect measurement of FeSe pure single crystals Ryo Ogawa, Atsutaka Maeda, Fuyuki Nabeshima Previous measurements of the effective viscous drag coefficient of the moving vortex show that, contrary to expectations, the vortex core is moderately clean in various clean superconductors [1], which has not been understood by existing theories. Therefore, we evaluated the quasiparticle electronic state in the core by an alternative technique of measuring the microwave flux-flow Hall effect using a newly developed method [2]. We performed the vortex Hall angle measurements of another candidate of clean superconductors, FeSe prepared by vapor transport method [3] to see how large the flux-flow Hall angle would be. As a result, the tangent of the Hall angle of FeSe is about 0.5, which is slightly smaller than those obtained by the conventional method [4]. Furthermore, the flux-flow Hall angle shows a non-monotonic magnetic field dependence. These are likely to be due to the cancellation of the hole and electron contributions, which is characteristic of multiband superconductors. |
Wednesday, March 16, 2022 10:00AM - 10:12AM |
M69.00007: Tuning antiferromagnetic fluctuations and superconductivity insingle layer FeSeS by chemical pressure Basu D Oli, Qiang Zou, Huimin Zhang, TATSUYA SHISHIDOU, Michael Weinert, Lian Li Single layer FeX (X = S, Se, Te) epitaxially grown on SrTiO3 (STO) substrate represents a model system for probing a host of quantum phenomena due to the interplay of topology, magnetism, and superconductivity. In this work, we investigate the impact of chemical pressure on the antiferromagnetic (AFM) fluctuations and superconductivity in single layer FeSe1-xSx/STO. |
Wednesday, March 16, 2022 10:12AM - 10:24AM |
M69.00008: Broken symmetry states in FeSe1-xSx measured with STM/S MORGAN A WALKER, Timothy J Boyle, Journey Byland, Marvin A Muller, Jakob Boeker, Zitong Zhao, Ryan P Day, Matteo Michiardi, Sergey Zhdanovich, Sergey Gorovikov, Tor Pedersen, Andrea Damascelli, Adrian Gozar, Ilya Eremin, Valentin Taufour, Eduardo H Da Silva Neto Strong electron correlations in cuprate high-temperature superconductors are known to be necessary for the emergence of exotic phases including and beyond superconductivity. Despite several phenomenological parallels between the cuprates and Fe-based superconductors, the degree to which strong correlations determine the phase diagram in the latter is uncertain. We used scanning tunneling microscopy and spectroscopy to investigate the local symmetries of the electronic states in FeSe1-xSx to search for possible signatures of strong correlations. An analysis of the energy dependence in our spectroscopic mappings, complemented by angle-resolved photoemission spectroscopy measurements and theoretical simulations, points to an electronic order that might originate from orbital-selective strong correlations. |
Wednesday, March 16, 2022 10:24AM - 10:36AM |
M69.00009: Fermi surface and upper critical field of FeSe under applied pressure Amalia I Coldea, Pascal Reiss, Thomas Bouteiller, Zachary Zajicek, Amir A Haghighirad, David E Graf Electronic nematic and spin-density wave phases of FeSe family of iron-chalcogenides superconductors can be intertwined and difficult to assess their relevance on superconductivity. A tuning parameter like applied pressure, which is a versatile clean tuning parameter, can be used to explore their relative importance. Here, we report a tunnel diode oscillator study of FeSe under pressure using both piston cell and diamond anvil cells up to 47 kbar. Using this contactless transport and thermodynamic measurement, we can detect quantum oscillations that change significantly their character outside the nematic phase and we determine the upper critical field behaviour as a function of applied pressure. The nature of this high-pressure electronic phase will be discussed. |
Wednesday, March 16, 2022 10:36AM - 10:48AM |
M69.00010: Specific Heat and the gap structure of a Nematic Superconductor, application to FeSe Kazi Ranjibul Islam, Andrey V Chubukov, Ilya Eremin, Jakob Boker We report the results of our in-depth analysis of spectroscopic and thermodynamic properties of a multi-orbital metal, like FeSe, which first develops a nematic order and then undergoes a transition into a superconducting state, which co-exists with nematicity. We analyze the angular dependence of the gap function and specific heat CV(T) of such nematic superconductor. We specifically address three issues: (i) angular dependence of the gap in light of the competition between nematicity-induced s-d mixture and orbital transmutation of low-energy excitations in the nematic state, (ii) the effect of nematicity on the magnitude of the jump of the specific heat CV(T) at Tc and the temperature dependence of CV(T) below Tc, and (iii) a potential transition at Tc1 < Tc from an s+d state to an s + ei η d state that breaks time-reversal symmetry. We consider two scenarios for a nematic order: scenario A, in which this order develops between dxz and dyz orbitals on hole and electron pockets and scenario B, in which there is an additional component of the nematic order for dxy fermions on the two electron pockets. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700