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 W55: Correlated Electron Materials II |
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Sponsoring Units: GMAG Chair: Colin Sarkis, Oak Ridge National Lab Room: Room 305 |
Thursday, March 9, 2023 3:00PM - 3:12PM |
W55.00001: Spin-orbit coupling controlled ground states in the double perovskite iridates A2BIrO6 (A = Ba, Sr; B = Lu, Sc) Adam A Aczel, Patrick Clancy, Qiang Chen, Clarina dela Cruz, Dalmau Reig-i-Plessis, Greg MacDougall, Chris Pollock, Mary Upton, Travis J Williams, Jeremy P Carlo, James W Beare, Graeme Luke, Haidong Zhou Iridates with the 5d4 electronic configuration have attracted recent interest due to reports of magnetically-ordered ground states despite longstanding expectations that their strong spin-orbit coupling would generate a J = 0 electronic ground state for each Ir5+ ion. The major focus of prior research has been on the double perovskite iridates Ba2YIrO6 and Sr2YIrO6, where the nature of the ground states (i.e. ordered vs non-magnetic) is still controversial. Here we present neutron powder diffraction, high energy resolution fluorescence detected x-ray absorption spectroscopy (HERFD-XAS), resonant inelastic x-ray scattering (RIXS), magnetic susceptibility, and muon spin relaxation data on the related double perovskite iridates Ba2LuIrO6, Sr2LuIrO6, Ba2ScIrO6, and Sr2ScIrO6 that enable us to gain a general understanding of the electronic and magnetic properties for this family of materials. Our HERFD-XAS and RIXS measurements establish J = 0 electronic ground states for the Ir5+ ions in all cases, with similar values for Hund's coupling JH and the spin-orbit coupling constant λSOC. Our bulk susceptibility and muon spin relaxation data find no evidence for long-range magnetic order or spin freezing, but they do exhibit weak magnetic signals that are consistent with extrinsic local moments. Our results indicate that the large λSOC is the key driving force behind the electronic and magnetic ground states realized in the 5d4 double perovskite iridates, which agrees well with conventional wisdom. |
Thursday, March 9, 2023 3:12PM - 3:24PM |
W55.00002: Abnormal magnetic moment with orbital degree of freedom Jong-hyeok Choi, Dong-hwan Kim, Jae-Hoon Park We investigate the effect from the competition between spin-orbit coupling (SOC) and exchange interaction on the magnetic moment of 3d transition metal system with orbital degree of freedom. The ground state of d 7 configuration in almost perfect Oh symmetry of Ba3CoSb2O9 possessing orbital degree of freedom is analyzed through X-ray absorption spectroscopy (XAS) on Co L2,3 edges. Abnormally reduced magnetic moment is derived by full multiplet cluster model calculation based on the spectrum. The XAS shows that the microscopic states of the Ba3CoSb2O9 and CoO are similar, but the calculation shows that the competing spin-orbit coupling and exchange interaction TN ~ 3.8 K and 300 K respectively, result the ground state ordered moment ~ 1.93 µB/Co2+ and conventional MM ~ 3.25 µB/Co2+ as reported. In this context, the general behavior of the MM of d 7 system beginning from the MM of Ba3CoSb2O9 with increasing TN will be presented, and furthermore the MM variation of d 2 system, especially of V2O3 case will be discussed. |
Thursday, March 9, 2023 3:24PM - 3:36PM |
W55.00003: Strongly correlated itinerant magnetism near superconductivity in a magnetically doped transition metal dichalcogenide Nikola Maksimovic, Ryan Day, Alexander Liebman-pelaez, Fanghui Wan, Na Hyun Jo, Aaron Bostwick, Eli Rotenberg, Sinead M Griffin, John Singleton, James G Analytis, Christopher Jozwiak Metallic ferromagnets with strongly interacting electrons often exhibit remarkable electronic phases such as ferromagnetic superconductivity, complex spin textures, and nontrivial topology. In this talk, I will discuss the synthesis of a layered magnetic metal NiTa4Se8 (or Ni1/4TaSe2) with a Curie temperature of 58 Kelvin. Magnetization data and density functional theory calculations indicate that the nickel atoms host uniaxial ferromagnetic order of about 0.7μB per atom, while an even smaller moment is generated in the itinerant tantalum conduction electrons. Strong correlations are evident in flat bands near the Fermi level, a high heat capacity coefficient, and a high Kadowaki-Woods ratio. Density functional theory calculations suggest that electron and hole Fermi surfaces in the ferromagnetic phase are associated with opposite spin polarization. When the system is diluted of magnetic ions, the samples become superconducting below about 2 Kelvin. I will briefly discuss possible mechanisms for superconductivity in this family. |
Thursday, March 9, 2023 3:36PM - 3:48PM |
W55.00004: Mn(Pt1-xPdx)5P: Isovalent Tuning of Mn Sublattice Magnetic Order Tyler J Slade, Ranuri S Dissanayaka Mudiyans, Nao Furukawa, Tanner R Smith, Juan Schmidt, Lin-Lin Wang, Sergey L Budko, Weiwei Xie, Paul C Canfield We report the discovery of MnPd5P, a rare-earth-free ferromagnet with TC = 295 K and conduct a substitutional study with its antiferromagnetic analogue MnPt5P. Based on measurements of the temperature and field dependent resistance and magnetization, we construct a temperature–composition phase diagram for Mn(Pt1-xPdx)5P. The AFM state in pure MnPt5P is extraordinarily sensitive to Pd substitution, and as little as x = 0.02 stabilizes purely FM order, with TC maximized at 320 K for x = 0.62. At dilute Pd levels, x < 0.01, both AFM and FM states are observed. Here, the single AFM transition in MnPt5P splits into a higher temperature PM to FM transition followed on cooling by a lower temperature FM to AFM transition and then by re-entry into the FM state with further cooling. We propose the fantastic sensitivity of the AFM phase in Mn(Pt1-xPdx)5P (x < 0.01) may be associated with change in the Fermi-surface topology, and show electronic band structure calculations are qualitatively in-line with this picture. |
Thursday, March 9, 2023 3:48PM - 4:00PM |
W55.00005: Quantum tuning of magnetic phases in vanadium sulphide single crystals Pedro Vianez, Cesar Sonego, Hui Li, Marcos A Avila, Stephen E Rowley Strongly correlated electron systems are known to host a variety of exotic phenomena and novel quantum phases. The transition-metal chalcogenide system, VxS8, is of particular interest, for it displays a wide range of behaviour on changing the stoichiometry, from a charge density wave metal (x=4) to an antiferromagnetic metal (x=5,6) and even, a paramagnet metal (x=8). Here, we focus on V5S8, showing how magnetic interactions between the vanadium d-electrons lead to an antiferromagnetic phase below 32K. We present high pressure resistivity data helping to shed light on whether the magnetic electrons are localized or itinerant. Heat capacity measurements up to 14T, reveal an intriguing T2 dependence below TN and down to low temperatures, as well as evidence for new magnetic phases at fields above the 4.5T spin-flop transition. |
Thursday, March 9, 2023 4:00PM - 4:12PM |
W55.00006: Electrical signatures of chiral quantum spin liquids Saikat Banerjee, Wei Zhu, Shi-zeng Lin Quantum spin liquid (QSL) has currently become an interesting topic in interacting spin systems which nevertheless do not order magnetically down to the lowest experimentally accessible temperature. Since its first proposal as a bosonic counterpart of fractional quantum Hall effect in a triangular lattice, the corresponding lattice has always remained a center of attention as a potential set-up to realize this state, however, conclusive evidence is still lacking. Motivated by the recent surge of theoretical and experimental interests in these systems, here, we revisit this state of a half-filled Hubbard model on the triangular lattice by focusing on its concomitant electrical signatures. We discuss the localized orbital currents utilizing mean-field parton description. Our analytical predictions are further supported by an unbiased density-matrix renormalization group (DMRG) calculation on the Hubbard model in an intermediate coupling regime. Our results show that the chiral QSL phase has a clear electromagnetic response even in a Mott insulator, which can facilitate the experimental detection of this long-sought-after phase. |
Thursday, March 9, 2023 4:12PM - 4:24PM |
W55.00007: High-pressure Synthesis of Cubic Perovskite KOsO3 and Its Incommensurate Magnetic Structure Jie Chen, Javier Gainza, Angel Muñoz, Hongze Li, Jiaming He, José Antonio Alonso, Jianshi Zhou The syntheses of LiOsO3 and NaOsO3 revived the long-standing dialogs of ferroelectric metal and the metal-insulator transition [1-4]. A cubic perovskite phase of KOsO3 in this family has been synthesized under a high-pressure and high-temperature condition for the first time. The neutron diffraction measurements were performed on the powder sample of KOsO3 at 100, 200, 300, 400 and 500 K. The nuclear structure of KOsO3 remains the simple cubic perovskite structure (Pm-3m) from 100 K to 500 K; surprisingly, its magnetic structure was determined to be incommensurate in the temperature range 100-500 K, and the propagation vector changes as temperature increases from 300 K to 500 K [figure 1 (b)]. In the talk, we will present the details of this rare incommensurate magnetic structure and its novel magnetism, as well as the electron transport and other physical properties of this new 5d perovskite. |
Thursday, March 9, 2023 4:24PM - 4:36PM |
W55.00008: Effect of substitution on the magnetic order in La2(AxNi1-x)7; A = Co, Cu Atreyee Das, RAQUEL A RIBEIRO, Sergey L Budko, Paul C Canfield Small moment magnetic systems attract attention as their magnetic ordering temperatures can often be tuned towards a quantum phase transition, using non-thermal parameters, to study exotic physical phenomena such as unconventional superconductivity, heavy Fermi liquid, etc. Specific heat, electrical resistivity, and low field magnetization measurements indicate that in parent La2Ni7 there is a series of AFM phase transitions at 61.0K, 56.5K, and 42.2K with a low saturated moment of 0.12μB/Ni [1]. Tuning with hydrostatic pressure up to 2GPa indicated very little pressure dependence of the transition temperatures. We study the chemical substitution of Ni with its adjacent neighbors, Co and Cu, to create a different type of perturbation. Single crystals of La2(AxNi1-x)7; A = Co, Cu have been synthesized and characterized. Both the substituted systems show a change of the magnetic state with temperature and field based on the M(H,T) measurements. Composite T-H-x phase diagrams will be presented to follow the evolution of magnetic transitions in doped La2Ni7. |
Thursday, March 9, 2023 4:36PM - 4:48PM |
W55.00009: Kitaev vs. Non-Kitaev Honeycomb Cobaltate Xiaoyu Liu, Hae-Young Kee Since a microscopic mechanism of the Kitaev interaction in honeycomb lattice was reported, several Kitaev materials where the Kitaev interaction is dominant over other symmetry-allowed interactions have been suggested. Cobaltate with 3d7 is one of them, and a previous theory showed that the cancellation of exchange paths that contribute to the Heisenberg interaction makes the Kitaev to be dominant. However, recent theoretic and experimental works found leading Heisenberg and negligible Kitaev interaction in BaCo2(AsO4)2. This calls for further study to clarify the origin of discrepancies. |
Thursday, March 9, 2023 4:48PM - 5:00PM |
W55.00010: Magnetic Ground States of Honeycomb Lattice Wigner Crystals Nitin Kaushal, Nicolás Morales-Durán, Allan H MacDonald, Elbio R Dagotto In recent years, moiré materials constructed using two layers of transition metal dichalcogenides have been used to simulate the Hubbard model on triangular lattice procuring strongly correlated physics in half-filled (n=1) flat bands. Lattice Wigner crystal states, at other fractional fillings like n=2/3, 1/2, and 1/3, are also stabilized by long-range Coulomb interactions in these two-dimensional triangular moiré lattices. Recent ab-initio work on the Gamma-valley transition metal dichalcogenide homobilayers unveiled effective moiré honeycomb lattices near the Fermi level. We employ large-scale unrestricted Hartree-Fock techniques to unveil the magnetic phase diagrams of honeycomb lattice Wigner crystals. For the three lattice filling factors with the largest charge gaps, n = 2/3, 1/2, 1/3, the magnetic phase diagrams contain multiple phases, including ones with non-collinear and non-coplanar spin arrangements. We discuss magnetization evolution with the external magnetic field, which has potential as an experimental signature of these exotic spin states. Our theoretical results[1] could potentially be validated in moiré materials formed from group VI transition metal dichalcogenide twisted homobilayers. |
Thursday, March 9, 2023 5:00PM - 5:12PM |
W55.00011: Synthesis, Structure and Magnetic Properties of a New Spin-1 Honeycomb Lattice KNiAsO4 with a Zig-Zag Magnetic Structure Duminda Sanjeewa Identifying and characterizing new honeycomb magnetic systems are the key ingredients to explore new candidate materials for the Kitaev model as the model realizes the exact quantum spin liquids ground state. Recently the Kitaev model with higher spins ( S = 1) systems have been proposed as candidate materials to host the quantum spin liquid state. Honeycomb compound, KNiAsO4, is one such magnetic system and here, we present a comprehensive series of magnetic and neutron scattering measurements and evaluate the potential for Kitaev physics via the experimental determination of the spin-Hamiltonian. Bulk magnetic measurements of KNiAsO4 reveal an antiferromagnetic transition at ∼ 19 K which is generally robust to applied magnetic fields. Neutron diffraction measurements show magnetic order with a k = ( 3/2 , 0, 0) ordering vector which results in the well-known “zigzag” magnetic structure thought to be adjacent to the spin-liquid ground state. Inelastic neutron scattering experiments show a well defined gapped spin-wave spectrum with no evidence of the continuum expected for fractionalized excitations. Modeling of the spin waves shows that the extended Kitaev spin-Hamiltonians is generally necessary to model the spectra and reproduce the observed magnetic order. Overall, our results demonstrate that the KNiAsO4 is a promising candidate to study Kitaev physics associate with spin-1 honeycomb system. |
Thursday, March 9, 2023 5:12PM - 5:24PM |
W55.00012: Correlated Electrons, Phase Transitions and Frustrated Magnetism in TiF3 GAYANATH W FERNANDO, Igor Maznichenko, Arthur Ernst, Pawel Buczek, Matthias R Geilhufe Transition metal trifluorides are known to exhibit fascinating physical properties such as the negative thermal expansion observed in ScF3 and several coupled structural and magnetic phase transitions. In this work, we focus on the electronic and magnetic properties of TiF3 (Ti carrying an extra valence d-electron compared to Sc) which is reported to have strongly correlated d electrons. At low temperature, TiF3 has a rhombohedral structure while above 370 K, it has the cubic perovskite structure AMX3 with no cation A present. |
Thursday, March 9, 2023 5:24PM - 5:36PM |
W55.00013: Frustrated magnetic state of Mott Insulating TiF3 Donal Sheets We present magnetic susceptibility, optical, and heat capacitance measurements of perovskite TiF3. We find that the optical response favors an insulating state with a local moment magnetic response consistent with an S = 1/2 local moment per Ti+3 ion. Analysis of the magnetism gives an antiferromagnetic exchange coupling with a net Weiss temperature of order 25 K. However, the system shows no susceptibility peak at this temperature scale and appears free of long-range antiferromagnetic order down to 3 K, thus promoting the status of this simple, nearly cubic perovskite structured material to a candidate spin liquid. |
Thursday, March 9, 2023 5:36PM - 5:48PM |
W55.00014: Unusual antiferromagnetism in Quasi-one-dimensional BaFe2Se4 and K3Fe2Se4 Nikhil Uday Dhale, Keith M Taddei, Wenhao Liu, Xiaoyuan Liu, Sheng Li, Diana Berman, Clarina dela Cruz, Rashad Kadado, Bing Lv Quasi-one-dimensional (Q-1D) chalcogenides have attracted increased attention recently due to the rich physics of exotic magnetic order, charge-density order, topological state, quantum spin hall effect, and emergent superconductivity discovered in these materials. Here we systematically synthesized and studied two ternary iron chalcogenides with the same FeSe4 tetrahedral building motif commonly seen in high-temperature iron chalcogenide superconductors. BaFe2Se4 and K3Fe2Se4 have similar Q-1D chain structures with edge-shared FeSe4 tetrahedral units whereas the latter shows a distorted structure and different iron valence state. Magnetic susceptibility and neutron powder diffraction unambiguously revealed antiferromagnetic structure in both compounds with TN ~ 310 K for BaFe2Se4 and TN ~ 110 K for K3Fe2Se4. However, BaFe2Se4 exhibits a canted antiferromagnetic structure with a net ferromagnetic moment, whereas K3Fe2Se4 shows block-type antiferromagnetic ordering despite their similar Q-1D building motifs. More results, their similarity and difference, and the implications will be discussed. |
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