Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session K39: 5d/4d Transition Metal Systems IIIFocus
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Sponsoring Units: DMP Chair: Qing Huang, Louisiana State University Room: Room 231 |
Tuesday, March 7, 2023 3:00PM - 3:36PM |
K39.00001: The mysterious oddness of strontium ruthenate's superconducting state: Strong electronic correlations and spin-orbit coupling in multi-orbital systems Invited Speaker: Olivier Gingras Recent experimental improvements have established key properties of the superconducting order parameter of strontium ruthenate, yet some of those give seemingly different pictures that are challenging to reconcile in a single theory [1, 2]. First reviewing these latest developments, we then present a numerical framework to study potential leading instabilities based on first-principles approaches and strong electronic correlations [3, 4]. The results highlight the importance of spin-orbit coupling in entangling electronic quantum numbers, yielding rich and complex order parameters. They suggest a rare type of order dominated by odd-frequency pairing as a prime candidate, which is also found using frequency-dependent linear response theory within dynamical mean-field theory. We discuss observable signatures in specific heat associated with these leading states and develop a static interpretation of odd-frequency pairings. |
Tuesday, March 7, 2023 3:36PM - 3:48PM |
K39.00002: Dynamic Jahn-Teller effect and emergent magnetism in cubic 5d1 double perovskites Naoya Iwahara, Liviu F Chibotaru Electron-phonon (vibronic) coupling changes the nature of the magnetism of spin-orbit Mott insulators: |
Tuesday, March 7, 2023 3:48PM - 4:00PM |
K39.00003: First-principles approach to spin-orbital dynamics of localized electrons Ryuta Iwazaki, Hiroshi Shinaoka, Shintaro Hoshino Among multi-orbital systems, 5d-electron systems, which host atoms having a large atomic number, the energy scales of the Coulomb interaction and the spin-orbit coupling are comparable, leading to rich physical phenomena. When we perform material-based theoretical research, we should use the parameters obtained from first-principles calculation, and treat the Coulomb interaction and the spin-orbit coupling accurately. However, it is challenging because of the huge computational cost. However, in the strong coupling limit where electrons are localized, we can treat both at a reasonable numerical cost. |
Tuesday, March 7, 2023 4:00PM - 4:12PM |
K39.00004: Melting transition in the van der Waals superlattice of self-intercalated 2H-TaS2 Thomas M Sutter For layered materials, the introduction of an atomic species into the van der Waals gap – known as intercalation – provides an avenue for modification of the electronic, magnetic, and structural properties of the parent compound. Recently, a class of ultra-thin, self-intercalated transition metal dichalcogenide materials have been realized, and shown to exhibit structural and magnetic ordering. Here, we demonstrate the post-growth intercalation of Ta into 2H-TaS2 through annealing 60 nm thick sample films that are initially in the 1T phase to 600 K. A 2 x 2 superlattice associated with ordering of the intercalate is observed in these annealed samples, and the dynamics of this superlattice are probed with ultrafast electron diffraction revealing a Debye-Waller like response at room temperature. The superlattice exhibits a reversible equilibrium order-disorder melting transition around 483 K. Additionally, the in-plane resistivity vs. temperature reveals significant suppression of the 3 x 3 CDW transition at 75 K, but two new anomalies are present: one at 231 K and one at 271 K. This work expands on the growing study of self-intercalated TMD's and outlines a simple process for post growth intercalation. |
Tuesday, March 7, 2023 4:12PM - 4:24PM |
K39.00005: Momentum-resolved EELS study of lattice excitations in 1T-TaS2 Farzaneh Hoveyda, Caitlin S Kengle, Xuefei Guo, Jin Chen, Simon L Bettler, Dipanjan Chaudhuri, Peter Abbamonte 1T-TaS2 is a well-known quasi two-dimensional (2D) transition metal dichalcogenide that exhibits three charge density wave (CDW) phases. At T<180K, this material enters a commensurate phase usually interpreted as a Mott insulator, which is often cited as a candidate quantum spin liquid. However, little is known about the charge excitations of 1T-TaS2 at nonzero momentum, q. Here, we present a study of the meV-scale charge excitations of this material using momentum-resolved EELS (M-EELS). The spectrum consists of one acoustic and two optical phonon branches whose dispersion is influenced by the CDW wave vector. I will discuss how these excitations evolve with temperature and their relevance to the formation of the Mott state. |
Tuesday, March 7, 2023 4:24PM - 4:36PM |
K39.00006: Magnetic anisotropy in 1T-TaS2 Muhammad Nauman, Valeska Zambra, Kimberly Modic, Brad Ramshaw, Ross D McDonald, Arkady Shekhter Belonging to the family of transition metal dichalcogenides, 1T-TaS2 has attracted significant attention for more than 40 years thanks to its extremely rich phase diagram, which results from significant electron-electron interactions. The material undergoes a series of charge-density wave transitions upon cooling before reaching a completely commensurate (CCDW) state at ~ 200K. The CCDW state is believed to be a Mott insulator -- albeit unaccompanied by magnetic order or even any sign of a local magnetic moment -- and has been dubbed a quantum spin liquid (QSL). |
Tuesday, March 7, 2023 4:36PM - 4:48PM |
K39.00007: Combining Electron-Phonon and Dynamical Mean Field Theory Calculations for Correlated Materials: Transport in the Correlated Metal Sr2RuO4 David Abramovitch, Jin-Jian Zhou, Jernej Mravlje, Antoine Georges, Marco Bernardi Electron-electron (e-e) and electron-phonon (e-ph) interactions combine in nontrivial ways in correlated materials, with their joint effects governing phenomena that range from transport to phase transitions and superconductivity. In this talk, we combine ab initio dynamical mean field theory (DMFT) and e-ph calculations to achieve a unified description of e-e and e-ph interactions in correlated electron systems. We apply this method to study the transport properties and spectral functions in the Hund's metal Sr2RuO4 (SRO), analyzing in detail the interplay of e-e and e-ph interactions. We show that the e-ph interactions in SRO are relatively weak, and account for only 10% of the resistivity when considered alone. However, when combined with DMFT, we find that e-ph interactions are significantly enhanced by the DMFT band renormalization, accounting for ∼30% of the resistivity in SRO for temperatures between 50 – 300 K. The resistivity computed with both e-e and e-ph interactions is in very good agreement with experiment, addressing the “missing resistivity” puzzle in SRO. We highlight two key differences between e-e and e-ph interactions in SRO: first, the e-e scattering exceeds the classical Planckian limit while e-ph scattering does not; second, the e-ph interactions show a significant momentum dependence, while the DMFT e-e interactions are local. Our results demonstrate a significant interplay of e-e and e-ph interactions in SRO beyond the Matthiessen’s rule.
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Tuesday, March 7, 2023 4:48PM - 5:00PM |
K39.00008: Electronic Structure and Magnetism of the Triple-layer Ruthenate Sr4Ru3O10 Richard M Martin, Garu Gebreyesus, Prosper Ngabonziza, Jonathan D Denlinger, Alexei V Fedorov, James W Allen We report electronic band structure calculations for Sr4Ru3O10 to analyze the character of the bands and compare with recent spin-resolved ARPES experiments [1]. That work has verified the primary predictions of our recently published calculations [2] and provided new information on the spectra. In this talk we examine in more detail the Fermi surfaces for the majority and minority spin bands and the narrow spin polarized bands near the Fermi energy. We consider the dependence on the functional used in the calculations and the role of the rotations of the oxygen octahedra, which have previously been argued to be important for stabilizing the ferromagnetism, and we analyze the contributions of the different layers to the magnetism and the individual bands. |
Tuesday, March 7, 2023 5:00PM - 5:12PM |
K39.00009: Theory of Pines' demon in multiband metals Edwin W Huang, Peter Abbamonte, Philip W Phillips In 1956, David Pines predicted the existence of an acoustic plasmon, dubbed a "demon", in metals with multiple and sufficiently distinct charge carrier species. Despite extensive searches, demons have not been observed directly until recent momentum-resolved electron energy-loss spectroscopy (M-EELS) experiments on Sr2RuO4. Here, we discuss the necessary and sufficient conditions for the existence of demons as a stable collective excitation in multiband metals. We derive expressions for the dispersion, intensity, and damping rate of the demon in terms of band structure parameters, thereby going beyond the heuristic assumptions in Pines' original arguments. Furthermore, we comment on the suitability of various experimental probes, including M-EELS, optical spectroscopy, and X-ray spectroscopy, for detecting demons, and we make predictions for other materials where demons may be present and observable in experiment. |
Tuesday, March 7, 2023 5:12PM - 5:24PM |
K39.00010: Spin contribution to the inverse Faraday effect in transition metals Shashi B Mishra, Sinisa Coh We investigated the systematic variation of spin contribution to the inverse Faraday effect (IFE) in transition metals using first-principles calculations. In the case of nonmagnetic metals with inversion symmetry, we emphasize the use of gauge-invariant IFE theory, as the bands are doubly degenerate. We observe that the IFE is dependent on spin-orbit coupling (SOC) and the band structure of the metal. The IFE increases as one descends the periodic table from 3d to 4d to 5d metals, primarily because the SOC increases with atomic number. We analyzed the IFE of these transition metals as a function of the light frequency. We found that the frequency dependence of the IFE often resembles the shape of the joint density of states. In addition, we employed the Wannier interpolation method to achieve faster convergence with respect to k-points. This study provides insight into the physics behind spin IFE and demonstrates a way to increase IFE through band structure tuning. |
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