Bulletin of the American Physical Society
APS March Meeting 2023
Las Vegas, Nevada (March 510)
Virtual (March 2022); Time Zone: Pacific Time
Session G55: 1D MagnetismFocus

Hide Abstracts 
Sponsoring Units: GMAG Chair: Daniel Pajerowski, Oak Ridge National Lab Room: Room 305 
Tuesday, March 7, 2023 11:30AM  12:06PM 
G55.00001: Uncovering new lowdimensional magnets: A computational toolbox and experimental results Invited Speaker: Daniel P Shoemaker A quantitative geometric predictor for the dimensionality of magnetic interactions has been released as a free searchable database. This predictor is based on networks of superexchange interactions and can be quickly calculated for crystalline compounds of arbitrary chemistry, occupancy, or symmetry. The resulting data are useful for classifying structural families of magnetic compounds. Starting with 42,520 compounds, we have classified and quantified compounds with 3d transition metal cations. The predictor reveals trends in magnetic interactions that are often not apparent from the space group of the compounds, such as triclinic or monoclinic compounds that are strongly 2D. We present specific cases where the predictor identifies compounds that should exhibit competition between 1D and 2D interactions, and how the predictor can be used to identify sparselypopulated regions of chemical space with asyetunexplored topologies of specific 3d magnetic cations. Use of the toolkit to identify new lowdimensional spin1/2 materials will be discussed, along with the prospects for future applications to rareearth systems. 
Tuesday, March 7, 2023 12:06PM  12:18PM 
G55.00002: Spins, magnons, and phonons in the quasi1D material MoI_{3} Topojit Debnath, Yuhang Liu, Yanbing Zhu, Felipe H Jornada, Fariborz Kargar, Alexander A Balandin, Roger K Lake Quasi1D materials are interesting for both basic and applied physics. MoI_{3 }has attracted special attention due to its strongly 1D character. In the Pmmn phase, each Mo atom is surrounded by 6 chalcogen atoms in distorted octahedral coordination forming dimerized chains. The chains are weakly coupled to neighboring chains in a triangular lattice. Density functional theory calculations find an antiferromagnetic (AFM) ground state with an easy plane perpendicular to the chains, alternating spins along the dimerized chains, and a spin spiral texture from chain to chain. The calculated magnetic moments of ~3 μ_{B} per Mo ion are consistent with Mo^{3+} with 3 electrons in the t_{2g} ground state resulting from the octahedral crystal field splitting. Exchange coupling constants are extracted for a Heisenbergtype magnetic Hamiltonian, which is then solved for the magnon dispersion using linear spin wave theory. The phonon spectrum is determined, and the frequencies of the phonon and magnon spectra match well with measured Raman peaks [1]. The anisotropic thermal conductivity is also determined from the phonon Boltzmann transport equation. 
Tuesday, March 7, 2023 12:18PM  12:30PM 
G55.00003: LT Scaling in Depleted Quantum Spin Ladders Stanislaw Galeski, Kirill Povarov, Dominic Blosser, Severian Gvasaliya, Rafa? Wawrzy?czak, Jacques Ollivier, Johannes Gooth, Andrey Zheludev Using a combination of neutron scattering, calorimetry, quantum Monte Carlo simulations, and analytic results we uncover confinement effects in depleted, partially magnetized quantum spin ladders. We show that introducing nonmagnetic impurities into magnetized spin ladders leads to the emergence of a new characteristic length L in the otherwise scalefree TomonagaLuttinger liquid (serving as the effective lowenergy model). This results in universal LT scaling of staggered susceptibilities. Comparison of simulation results with experimental phase diagrams of prototypical spin ladder compounds bis(2,3dimethylpyridinium)tetrabromocuprate(II) (DIMPY) and bis(piperidinium)tetrabromocuprate(II) (BPCB) yields excellent agreement. 
Tuesday, March 7, 2023 12:30PM  12:42PM 
G55.00004: Experimental evaluation of quantum entanglement measures in spin chain systems Lazar L Kish, Lisuo Wu, Leonid Vasylechko, Andrey Podlesnyak, Igor A Zaliznyak Fractionalized excitations in quantum magnets such as 1D Heisenberg S=1/2 systems (quantum spin chains) are known to present evidence of quantum entangled states. Conventionally, systems with larger angular momenta (S≥3/2) are closer to the classical limit and therefore quantum entanglement is less important. Some rare earth systems nevertheless exhibit S=1/2 physics due to the selection of groundstate Kramers doublets by strong spinorbit coupling and crystal electric fields. Here we present analysis of inelastic neutron scattering experiments, aiming to evaluate how the prevalence of quantum collective behavior (multipartite entanglement) manifests itself in the effective S=1/2 case of a rare earth Yb ion. We turn to recent advances to the analysis of neutron spectra, which have shown it possible to calculate certain modelindependent measures of multipartite entanglement. These entanglement measures, such as the quantum Fisher information, can place quantitative bounds on the degree of entanglement which may be present in a system. These have already been evaluated by others on KuCF_{3 }[1], a system of weakly coupled S=1/2 chains. Here, we analyze entanglement measures in a rare earth material YbAlO_{3}[2], which demonstrates clear twospinon spectra characteristic of quantum spin chains and compare it with the case of a higherspin transition metal system. Special attention is paid to the behavior of these entanglement measures at magnetic field and temperature points near known thermal and quantum phase transitions. 
Tuesday, March 7, 2023 12:42PM  1:18PM 
G55.00005: Critical LowEnergy Spin Dynamics in the BECType Antiferromagnets Invited Speaker: Mladen Horvatic The NMR nuclear spinlattice relaxation rate (1/T_{1}) data in quantum spin systems provide privileged access to lowenergy spin fluctuations and are directly comparable to theoretical predictions for the corresponding spinspin correlation functions. In particular, gapless quasi1D systems are addressed by the TomonagaLuttinger Liquid (TLL) theory, a purely 1D, effective, lowenergy description, providing a 1Dcritical, powerlaw prediction for the temperature (T) dependence of 1/T_{1}. We showed that in real compounds an RPAbased correction factor has to be applied to this powerlaw, in order to account for the enhancement of the 1/T_{1} rate induced by the 3Dcritical fluctuations related to the lowT BEC ordering. Using this TLL+RPA description, we successfully fitted the 1/T_{1}(T) data in a spinladder compound (C_{7}H_{10}N)_{2}CuBr_{4} (DIMPY) and in an Ising spin chain BaCo_{2}V_{2}O_{8}, providing thereby the first direct determination of the TLL interaction parameter K that confirms the theoretical predictions [1]. 
Tuesday, March 7, 2023 1:18PM  1:30PM 
G55.00006: Firstprinciples investigation of the electronic and magnetic properties of quasionedimensional MoBr_{3} KARUNA K PILLALA, Se Young Park We investigate the electronic and magnetic properties of molybdenum tribromide, MoBr_{3} using firstprinciples density functional theory. MoBr_{3} consists of weakly coupled onedimensional chains in which each Mo^{3+} ion is surrounded by a Br octahedron, facesharing with neighboring octahedra. The ground state structure exhibits dimerization of MoMo pairs with alternating short and long bonds, consistent with the experimental report. We find an insulating ground state with antiferromagnetic ordering having a magnetic moment of 1.8 µ_{B} on each Mo atom, smaller than the fully polarized value of 3 µ_{B} from the d^{3} filling of Mo, indicating orbitaldependent hybridization, which reduces the magnetic moment of Mo d_{z}^{2} orbitals extending along the dimer direction. Comparison of the electronic structures of dimerized and nondimerized antiferromagnetic phases shows that the dimerized phase is preferred. Energy lowering by a bondingantibonding splitting of the Mod_{z}^{2} bands from dimerization is larger than increasing the magnetic moment without dimerization, indicating the dominant interorbital hopping exceeding the Hund coupling for the d_{z}^{2} orbitals. We identify the interplay between onsite and intersite interaction in the system with nominal Mod^{3} filling leads to orbitaldependent suppression of the magnetic moments, manifested from the quasi onedimensional geometry. 
Tuesday, March 7, 2023 1:30PM  1:42PM 
G55.00007: Neutron diffraction studies on the Pr_{3}HfBi_{5} magnetic structure Rebecca L Dally, Jason F Khoury, Leslie M Schoop Members of the Ln3MBi5 family (Ln=Pr, Nd, Sm; M=Zr, Hf) crystallize in the P6_{3}/mcm space group, hosting the antiHf5Sn3Cu structure type. [1] Hypervalent Bi^{2−} chains and facesharing MBi_{6} octahedra form onedimensional chains along the caxis, and a framework of Ln^{3+} cations charge balances and separates the two motifs. The local symmetry of the Ln ion is orthorhombic, which for Pr^{3+} splits the J = 4 multiplet into 9 singlets and would typically result in a nonmagnetic Pr^{3+} ion. However, Pr_{3}HfBi_{5} orders antiferromagnetically at 4 K with a wavevector k = (1/2, 1/2, 1/10). Bulk magnetization measurements further show strong magnetic anisotropy, with a broad ordering temperature in susceptibility along the caxis, and a sharp transition within the abplane. Here, we present neutron diffraction results on the magnetic structure of Pr_{3}HfBi_{5} and compare to the magnetic structures of isostructural materials. For example, Pr_{3}TiSb_{5} is nonmagnetic [2] despite the PrPr bonds being closer together than in Pr_{3}HfBi_{5}, where an increase in the exchange coupling strength would be expected, suggesting that subleties in the CEF splitting lead to the long range magnetic order here. 
Tuesday, March 7, 2023 1:42PM  1:54PM 
G55.00008: Magnetic Field Induced Transitions in Spin1 Antiferromagnet NiNb_{2}O_{6} Subhash Thota, Maruthi R Recent observations of quantum critical excitations (QCE) in columbite systems such as NiNb_{2}O_{6} and CoNb_{2}O_{6} have brought great attention to the field of Quantum Materials so that QCE can be realized for T > 0 K. [1,2]. Here we present detailed studies of magnetic field induced transitions in NiNb_{2}O_{6 }mapped on the fieldtemperature (HT) phase diagram. The crystal structure analysis of the prepared sample of NiNb_{2}O_{6} using Xray diffraction and Rietveld refinement reveals orthorhombic crystal structure of space group is Pbcn (D_{2h}^{14}) with lattice parameters a = 14.038(3) Å, b = 5.684(3) Å and c = 5.025(3) Å. The unit cell essentially consists of layers of Ni–Nb–Nb–Ni–Nb–Nb–Ni with slightly distorted hexagonalclosedpacked oxygen octahedra perpendicular to the aaxis. Lowtemperature magnetic susceptibility (χT) measurements reveal antiferromagnetic (AFM) behavior below the Néel temperature T_{N }~ 5.8 K along with two field induced transitions at H_{C1} ~ 9.7 kOe and H_{C2} ~ 27.8 kOe. The best fits of χ vs. T data for T > 40 K to modified CurieWeiss law χ = χ_{0 }+ C/(Tθ) with χ_{0} = 2.3 × 10^{4}_{ }emu mol^{1 }Oe^{1} yield θ = +11 K, and C = 1.36 emu K mol^{1 }Oe^{1}, the latter yielding the effective magnetic moment µ = 3.3 µ_{B }/Ni^{2+} ion confirming the effective spin S = 1 and g = 2.3,_{ }and the principal exchange interaction J_{0} being ferromagnetic as in CoNb_{2}O_{6 }[3]. The HT phase diagram mapped using the MH isotherms and χ T data at different fields will be discussed along with the intrachain (J_{0}) and interchain (J_{1} and J_{2}) exchange interactions determined from H_{C1 }and H_{C2}. 
Tuesday, March 7, 2023 1:54PM  2:06PM 
G55.00009: Quasiballistic transport and longliving fermionic excitations in longrange anisotropic Heisenberg model Jacek Herbrych, Marcin Mierzejewski Purely ballistic transport is a rare feature even for integrable models. By numerically studying the Heisenberg chain with the powerlaw exchange, J∼1/r^{α}, where r is a distance, we show that for spin anisotropy Δ≈exp(α+2) the system exhibits a quasiballistic spin transport and the presence of fermionic exictations which do not decay up to extremely long times ∼10^{3}/J. This conclusion is reached on the base of the dynamics of spin domains, the dynamical spin conductivity, inspecting the matrix elements of the spincurrent operator, and by the analysis of most conserved operators. Our results smoothly connects two models where fully ballistic transport is present: free particles with nearestneighbor hopping and the isotropic HaldaneShastry model. 
Tuesday, March 7, 2023 2:06PM  2:18PM 
G55.00010: Phase Transitions in the Ferromagnetic Region of the spinS BilinearBiquadratic Spin Chain Isao MARUYAMA, Shin Miyahara We study ferromagnetic region of the spinS bilinearbiquadratic spin chain. While the spin S=1 case has been massively studied, higherS case has been less studied. In this study, we focus on the ferromagnetic region in the higherS case and find an exact phasetransition point between fully polarized ferromagneticphase and partially polarized ferromagneticphase by using numerical exactdiagonalization method up to S=3. The partially polarized ferromagneticphase has fractional magnetization M=11/(2S) under zero magneticfield; for example, M=2/3 for S=3/2, and M=3/4 for S=2. In addition, at a high symmetric point in the partially polarized ferromagneticphase, we find rigorous eigenstate correspondence between spinS model and spin1/2 antiferromagnetic model, which can be generalized to any dimensional lattices. This is nothing but ``spin1/2 liquefaction'' of ferromagnet. Even after spontaneous magnetization, the ground state has quantum entanglement due to a spin1/2 antiferromagnetic quantum state in ferromagnetic classical background. External magnetic field generated by this ``fractional ferromagnet'' has the potential to become a manipulation handle of an entangled quantum state in the context of quantum computer science. 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2023 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700