Bulletin of the American Physical Society
APS March Meeting 2024
Monday–Friday, March 4–8, 2024; Minneapolis & Virtual
Session Q22: Quantum Spin Liquids II: New Candidate MaterialsFocus
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Sponsoring Units: GMAG Chair: Benjamin Frandsen, Brigham Young University Room: 101B |
Wednesday, March 6, 2024 3:00PM - 3:36PM |
Q22.00001: New Directions in Spin-Liquid Materials Invited Speaker: Tyrel M McQueen
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Wednesday, March 6, 2024 3:36PM - 4:12PM |
Q22.00002: Quantum spin liquid on the surface of 1T-TaS2 and its detection scheme Invited Speaker: Chao-Kai Li The classification of various topological phases has attracted tremendous interests in recent years. It is understood that certain 2D quantum spin liquids (QSL) cannot be realized in strictly 2D systems, but can be realized on the surface of 3D systems. However, from the material's point of view, the realization of such surface QSL, including those realizable in pure 2D systems, is still lacking. |
Wednesday, March 6, 2024 4:12PM - 4:24PM |
Q22.00003: Spinon continuum in the Heisenberg quantum spin-chain compound Sr2V3O9 Matthew B Stone, Shang Gao, Ling-Fang Lin, Pontus Laurell, Qiang Chen, Qiang Huang, Clarina R dela Cruz, Krishnamurthy V Vemuru, Mark D Lumsden, Stephen E Nagler, Gonzalo Alvarez, Elbio R Dagotto, Haidong Zhou, Andrew Christianson We use inelastic neutron scattering to probe the magnetic excitations in a single crystal sample of the proposed S=1/2 linear chain antiferromagnet Sr2V3O9. The primary excitations associated with the S=1/2 linear chain Heisenberg antiferromagnet are fractional quasiparticles known as spinons. A spinon continuum with a bandwidth of approximately 22 meV is found to exist Sr2V3O9. We observe that the magnetic chain axis is along a direction nearly perpendicular to the apparent structural chains which exist in the compound. Although the system exhibits long range magnetic order below TN~5 K, we can consistently reproduce the spinon spectrum over a range of higher temperatures and energy transfers via comparisons to Bethe ansatz calculations, matrix renormalization group (DMRG) calculations, and effective field theories near the antiferromagnetic zone center. |
Wednesday, March 6, 2024 4:24PM - 4:36PM |
Q22.00004: Spin correlations in the S = 1/2 square-lattice antiferromagnet Sr2CuTe1-xWxO6 with a spin-liquid-like ground state Otto Mustonen, Ellen Fogh, Joseph Paddison, Lucile Mangin-Thro, Thomas Hansen, Helen Playford, Maria Diaz-Lopez, Peter Babkevich, Sami Vasala, Maarit Karppinen, Edmund J Cussen, Henrik M Ronnow, Helen C Walker The S = 1/2 square-lattice Heisenberg model has a predicted, but never observed, quantum spin liquid ground state for J2/J1 = 0.4-0.6 [1]. Isostructural double perovskites Sr2CuTeO6 and Sr2CuWO6 are physical realisations of this model with Néel (J1 ≫ J2) and columnar (J2 ≫ J1) antiferromagnetic order, respectively. The solid solution Sr2CuTe1-xWxO6 has a spin-liquid-like ground state in a wide region of x = 0.05-0.6 [2]. Here we show using polarized neutron scattering, that the spin correlations in two spin-liquid-like samples x = 0.2 and 0.5 are distinctly different and related to the parent phases [3]. Moreover, our neutron diffraction experiment on the W-rich ordered samples reveals two magnetic phases with antiferromagnetic and ferromagnetic order along c. Disorder in the interlayer Jc is therefore the likely cause of the suppression of magnetic order at x ≈ 0.6. These results highlight the complex magnetism of Sr2CuTe1-xWxO6 and hint at a new quantum critical point at x ≈ 0.3, where the spin correlations cross over from Néel to columnar-like. |
Wednesday, March 6, 2024 4:36PM - 4:48PM |
Q22.00005: On the Groundstate of the Novel SSL Material Yb2Be2GeO7 Mathew C Pula, Graeme Luke, Sarah R Dunsiger, Sudarshan Sharma, Jonah Gautreau, Amit Kanigel, Sajilesh K. P., Matthias D Frontzek We present experimental evidence for a spin liquid groundstate in a novel Shastry-Sutherland lattice material Yb2Be2GeO7. Yb2Be2GeO7 shows no sign of a magnetic phase transition in SQUID magnetometry, nor specific heat capacity. No magnetic Bragg peaks are detected in elastic neutron diffraction. Muon spin spectroscopy reveals persistent spin dynamics down to 18mK. The lack of magnetic order and presence of persistent spin dynamics strongly suggest a spin liquid groundstate. |
Wednesday, March 6, 2024 4:48PM - 5:00PM |
Q22.00006: NMR investigation of the quantum spin liquid candidate Na3Sc2(MoO4)2Mo3O8 Louis Beaudoin, Jeffrey A Quilliam, Ryan P Sinclair, Qing Huang, Haidong Zhou, Qiang Chen, Aime Verrier In recent years, we have witnessed a growing interest in quantum spin liquids (QSLs) for their unconventional fractional excitations such as spinons and Majorana fermions and for possible applications in quantum computing. While the origin of likely QSL states in systems with a standard kagome lattice is fairly evident, a number of molybdate materials with a more complicated model have also recently been shown to be strong QSL candidates [1]. Here we present our NMR results on the [Mo3]11+-based molecular magnet, Na3Sc2(MoO4)2Mo3O8. This spin-1/2 Heisenberg kagome system shows no long-range ordering or spin freezing down to 20mK according to µSR measurements [1], pointing towards a dynamical QSL ground state. Here, we present 23Na Knight shift and spin-lattice relaxation rate measurements that allow us to measure this material’s intrinsic, local susceptibility and probe the spin fluctuations induced by exotic gapless spin excitations. |
Wednesday, March 6, 2024 5:00PM - 5:12PM |
Q22.00007: Possible QSL realisation in the honeycomb system Cu3LiRu2O6 with Ru4+ (4d4) Avinash V Mahajan, Sanjay Bachhar, Surjeet Singh, Nashra Pistawala, Michael Baenitz, Joerg Sichelschmidt Honeycomb systems containing ions with a large spin orbit coupling and a nominally non-magnetic single-ion state have been proposed to host novel magnetic ground states [Phys. Rev. Lett. 111, 197201 (2013)]. Our susceptibility data on Cu3LiRu2O6 (containing Ru4+ (4d4)) exhibit a broad maximum around 300 K and a Curie-Weiss fit of the data above 300 K yields an effective moment of 2.42 μB and a Curie-Weiss temperature θCW = -222 K. There is no evidence of magnetic order down to 300 mK in heat capacity which varies as T2 at low-T. The finite T-independent 7Li NMR shift down to 2 K indicates a finite spin susceptibility and hence a magnetic state. The 7Li NMR spin lattice relaxation rate shows no evidence of magnetic order and varies linearly with temperature at low-T which is reminiscent of a Fermi liquid. Our results point towards the observation of excitonic magnetism in a d4 system together with the stabilisation of a spin liquid state at low-T. |
Wednesday, March 6, 2024 5:12PM - 5:24PM |
Q22.00008: Bond Dependent Exchange Interactions in the Honeycomb Quantum Magnet ErCl3 Andrew Treglia ErCl3 hosts honeycomb layers of Er3+ with an effective spin ½ ground state and anisotropic exchange interactions. Previous magnetic susceptibility and powder/single crystal neutron diffraction experiments (performed before the advent of the celebrated Kitaev honeycomb model) revealed a transition into a 120° antiferromagnetic order at 350 mK. At the time of the initial determination of this magnetic structure, no proposal for the interactions that could lead to this state was made. Magnetic models back then could not account for this particular magnetic structure. However, within the past 5 years, it has been shown that this phase can be stabilized through modern quantum field theories, such as in the Kitaev or other, more general compass models. Furthermore, numerical analysis of the Kitaev-Gamma-Heisenberg (KGammaH) model suggests that, when Kitaev and Heisenberg interactions compete on the honeycomb lattice, this 120° phase borders a quantum spin liquid phase, which leaves open the possibility of experimentally accessing this highly sought-after state of matter. We are attempting to quantify the magnetic interactions that are present in ErCl3 via inelastic neutron scattering and thermodynamic experiments. By fitting our data with these modern models, we hope to show that these exotic new ideas in physics can be experimentally observed in this class of rare-earth materials, providing the scientific community with new routes to test their ever evolving theories. |
Wednesday, March 6, 2024 5:24PM - 5:36PM |
Q22.00009: Zig-Zag ground state and potential Kitaev interactions in the spin-1 honeycomb material KNiAsO4 Keith M Taddei, Ovidiu O Garlea, Anjana M Samarakoon, Duminda Sanjeewa, Jie Xing, Tom W Heitmann, Clarina R dela Cruz, Athena S Sefat, David S Parker Despite the exciting implications of the Kitaev spin Hamiltonian, finding and confirming the quantum spin-liquid state have proven incredibly difficult. Recently, the applicability of the model has been expanded through the development of a microscopic description of a spin-1 Kitaev interaction. Here we explore a candidate spin-1 honeycomb system, KNiAsO4, which meets many of the proposed criteria to generate such an interaction. Neutron diffraction measurements show magnetic order at 19 K which results in the well-known “zig-zag” 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 fractionalized excitations found in the spin-1/2 model. Modeling of the spin waves using linear spin-wave theory together with a machine learning based optimization shows that the extended Kitaev spin Hamiltonian is generally necessary to model the spectra and reproduce the observed magnetic order. These results suggest that KNiAsO4 may be a candidate to study spin-1 Kitaev physics. |
Wednesday, March 6, 2024 5:36PM - 5:48PM |
Q22.00010: Spin-orbit coupled insulators and metals on the verge of Kitaev spin liquids in ilmenite heterostructures Yi-Feng Zhao, Seong-Hoon Jang, Yukitoshi Motome Competition and cooperation between the relativistic spin-orbit coupling and electron correlations give rise to various exotic quantum phenomena in solids. One such example is quantum spin liquids in magnets, which exhibit remarkable features such as topological orders and fractional excitations and could be realized in the Kitaev honeycomb model. Here we theoretically investigate hexagonal heterostructures including a candidate for the Kitaev magnets, an ilmenite oxide MgIrO3, to actively manipulate the electronic and magnetic properties toward the realization of the Kitaev spin liquids, by combining first-principles calculations and the effective model approaches. For three different types of bilayers MgIrO3/ATiO3 with A=Mn, Fe, Co, and Ni, we find that the spin-orbit coupled bands characterized by the pseudospin jeff = 1/2, crucially important for the Kitaev-type interactions, are retained in the MgIrO3 layer for all the heterostructures, but the band gap and the magnetic state depend on the types of the heterostructures as well as the A atoms. In particular, one type becomes metallic irrespective of A, while the other two are insulating. We show that the insulating cases realize dominant Kitaev-type interactions with different combinations of subdominant interactions depending on the type and A. Our results indicate that these hexagonal heterostructures are a good platform for engineering the magnetism and insulator-metal transitions in the spin-orbit coupled correlated materials. |
Wednesday, March 6, 2024 5:48PM - 6:00PM |
Q22.00011: Type-II heavy Fermi liquids and the magnetic memory of 4Hb-TaS2 Elio J König The interplay of quantum spin liquids with itinerant conduction electrons is of crucial interest for understanding layered structures composed of frustrated magnet and metal monolayers. Using parton-mean-field theory, we here demonstrate that a type-II heavy Fermi liquid, which is characterized by a vortex lattice in the slave boson condensate, can occur in the vicinity of the quantum phase transition separating fractionalized and heavy Fermi liquid phases. The magnetic flux threading each such vortex is parametrically smaller than the magnetic flux threading vortices in type-II superconductors. This makes a magnetic observation of this effect challenging. We propose scanning tunneling spectroscopy instead and investigate its signatures. If a type-II heavy Fermi liquid is cooled into a type-II superconductor, vortices in the slave boson condensate and in the superconducting condensate mutually attract. We argue that the type-II heavy Fermi liquid thereby provides a compelling explanation for the magnetic memory observed recently [Persky extit{et al.}, Nature extbf{609}, 692 (2022)] in thermal cycles of 4Hb-TaS2. |
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