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Electronic and magnetic properties of intermetallic Kagome magnets $R$V$_6$Sn$_6$ ($R$ = Tb - Tm)
Authors:
X. X. Zhang,
Z. Y. Liu,
Q. Cui,
N. N. Wang,
L. F. Shi,
H. Zhang,
X. L. Dong,
J. P. Sun,
Z. L. Dun,
J. G. Cheng
Abstract:
We present a systematic study of the structure, electronic, and magnetic properties of a new branch of intermetalllic compounds, $R$V$_6$Sn$_6$ ($R$ = Tb - Tm) by using X-ray diffraction, magnetic susceptibility, magnetization, electrical transport, and heat-capacity measurements. These compounds feature a combination of a non-magnetic vanadium kagome sublattice and a magnetic rare-earth triangula…
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We present a systematic study of the structure, electronic, and magnetic properties of a new branch of intermetalllic compounds, $R$V$_6$Sn$_6$ ($R$ = Tb - Tm) by using X-ray diffraction, magnetic susceptibility, magnetization, electrical transport, and heat-capacity measurements. These compounds feature a combination of a non-magnetic vanadium kagome sublattice and a magnetic rare-earth triangular sublattice that supports various spin anisotropies based on different $R$ ions. We find magnetic orders for the $R$ = Tb, Dy, and Ho compounds at 4.4, 3, 2.5 K, respectively, while no ordering is detected down to 0.4 K for the $R$ = Er and Tm compounds with easy-plane anisotropies. Electronically, we found no superconductivity or charge ordering transition down to 0.4 K for any member of this family, while all compounds exhibit multi-band transport properties that originate from the band topology of the vanadium kagome sublattice.
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Submitted 12 June, 2022;
originally announced June 2022.
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Emergence of superconductivity on the border of antiferromagnetic order in RbMn6Bi5 under high pressure: A new family of Mn-based superconductors
Authors:
P. T. Yang,
Q. X. Dong,
P. F. Shan,
Z. Y. Liu,
J. P. Sun,
Z. L. Dun,
Y. Uwatoko,
G. F. Chen,
B. S. Wang,
J. -G. Cheng
Abstract:
The advances in the field of unconventional superconductivity are largely driven by the discovery of novel superconducting systems. Here we report on the discovery of superconductivity on the border of antiferromagnetic order in a quasi-one-dimensional RbMn6Bi5 via measurements of resistivity and magnetic susceptibility under high pressures. With increasing pressure, its antiferromagnetic transiti…
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The advances in the field of unconventional superconductivity are largely driven by the discovery of novel superconducting systems. Here we report on the discovery of superconductivity on the border of antiferromagnetic order in a quasi-one-dimensional RbMn6Bi5 via measurements of resistivity and magnetic susceptibility under high pressures. With increasing pressure, its antiferromagnetic transition with TN = 83 K at ambient pressure is first enhanced moderately and then suppressed completely at a critical pressure of Pc = 13 GPa, around which bulk superconductivity emerges and exhibits a dome-like Tc(P) with a maximal Tc_onset = 9.5 K at about 15 GPa. Its temperature-pressure phase diagram resembles those of many magnetism-mediated superconducting systems. In addition, the superconducting state around Pc is characterized by a large upper critical field μ0Hc2(0) exceeding the Pauli limit, elaborating a possible unconventional paring mechanism. The present study, together with our recent work on KMn6Bi5 (Tcmax = 9.3 K), makes AMn6Bi5 (A= Alkali metal) a new family of Mn-based superconductors with relatively high Tc.
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Submitted 31 January, 2022;
originally announced January 2022.
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Unraveling the Topological Phase of ZrTe$_5$ via Magneto-infrared Spectroscopy
Authors:
Y. Jiang,
J. Wang,
T. Zhao,
Z. L. Dun,
Q. Huang,
X. S. Wu,
M. Mourigal,
H. D. Zhou,
W. Pan,
M. Ozerov,
D. Smirnov,
Z. Jiang
Abstract:
For materials near the phase boundary between weak and strong topological insulators (TIs), their band topology depends on the band alignment, with the inverted (normal) band corresponding to the strong (weak) TI phase. Here, taking the anisotropic transition-metal pentatelluride ZrTe$_5$ as an example, we show that the band inversion manifests itself as a second extremum (band gap) in the layer s…
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For materials near the phase boundary between weak and strong topological insulators (TIs), their band topology depends on the band alignment, with the inverted (normal) band corresponding to the strong (weak) TI phase. Here, taking the anisotropic transition-metal pentatelluride ZrTe$_5$ as an example, we show that the band inversion manifests itself as a second extremum (band gap) in the layer stacking direction, which can be probed experimentally via magneto-infrared spectroscopy. Specifically, we find that the band anisotropy of ZrTe$_5$ features a slow dispersion in the layer stacking direction, along with an additional set of optical transitions from a band gap away from the Brillouin zone center. Our work identifies ZrTe5 as a strong TI at liquid helium temperature and provides a new perspective in determining band inversion in layered topological materials.
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Submitted 25 July, 2020; v1 submitted 30 March, 2020;
originally announced March 2020.
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Machine Learning Assisted Insight to Spin Ice Dy$_2$Ti$_2$O$_7$
Authors:
Anjana M Samarakoon,
Kipton Barros,
Ying Wai Li,
Markus Eisenbach,
Qiang Zhang,
Feng Ye,
Z. L. Dun,
Haidong Zhou,
Santiago A. Grigera,
Cristian D. Batista,
D. Alan Tennant
Abstract:
Complex behavior poses challenges in extracting models from experiment. An example is spin liquid formation in frustrated magnets like Dy$_2$Ti$_2$O$_7$. Understanding has been hindered by issues including disorder, glass formation, and interpretation of scattering data. Here, we use a novel automated capability to extract model Hamiltonians from data, and to identify different magnetic regimes. T…
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Complex behavior poses challenges in extracting models from experiment. An example is spin liquid formation in frustrated magnets like Dy$_2$Ti$_2$O$_7$. Understanding has been hindered by issues including disorder, glass formation, and interpretation of scattering data. Here, we use a novel automated capability to extract model Hamiltonians from data, and to identify different magnetic regimes. This involves training an autoencoder to learn a compressed representation of three-dimensional diffuse scattering, over a wide range of spin Hamiltonians. The autoencoder finds optimal matches according to scattering and heat capacity data and provides confidence intervals. Validation tests indicate that our optimal Hamiltonian accurately predicts temperature and field dependence of both magnetic structure and magnetization, as well as glass formation and irreversibility in Dy$_2$Ti$_2$O$_7$. The autoencoder can also categorize different magnetic behaviors and eliminate background noise and artifacts in raw data. Our methodology is readily applicable to other materials and types of scattering problems.
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Submitted 11 November, 2020; v1 submitted 26 June, 2019;
originally announced June 2019.
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Landau quantization in coupled Weyl points: a case study of semimetal NbP
Authors:
Y. Jiang,
Z. L. Dun,
S. Moon,
H. D. Zhou,
M. Koshino,
D. Smirnov,
Z. Jiang
Abstract:
Weyl semimetal (WSM) is a newly discovered quantum phase of matter that exhibits topologically protected states characterized by two separated Weyl points with linear dispersion in all directions. Here, via combining theoretical analysis and magneto-infrared spectroscopy of an archetypal Weyl semimetal, niobium phosphide, we demonstrate that the coupling between Weyl points can significantly modif…
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Weyl semimetal (WSM) is a newly discovered quantum phase of matter that exhibits topologically protected states characterized by two separated Weyl points with linear dispersion in all directions. Here, via combining theoretical analysis and magneto-infrared spectroscopy of an archetypal Weyl semimetal, niobium phosphide, we demonstrate that the coupling between Weyl points can significantly modify the electronic structure of a WSM and provide a new twist to the protected states. These findings suggest that the coupled Weyl points should be considered as the basis for analysis of realistic WSMs.
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Submitted 8 November, 2018;
originally announced November 2018.
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Evolution of the magnetic and structural properties of Fe$_{1-x}$Co$_x$V$_2$O$_4$
Authors:
R. Sinclair,
J. Ma,
H. B. Cao,
T. Hong,
M. Matsuda,
Z. L. Dun,
H. D. Zhou
Abstract:
The magnetic and structural properties of single crystal Fe$_{1-x}$Co$_x$V$_2$O$_{4}$ samples have been investigated by performing specific heat, susceptibility, neutron diffraction, and X-ray diffraction measurements. As the orbital-active Fe$^{2+}$ ions with larger ionic size are gradually substituted by the orbital-inactive Co$^{2+}$ ions with smaller ionic size, the system approaches the itine…
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The magnetic and structural properties of single crystal Fe$_{1-x}$Co$_x$V$_2$O$_{4}$ samples have been investigated by performing specific heat, susceptibility, neutron diffraction, and X-ray diffraction measurements. As the orbital-active Fe$^{2+}$ ions with larger ionic size are gradually substituted by the orbital-inactive Co$^{2+}$ ions with smaller ionic size, the system approaches the itinerant electron limit with decreasing V-V distance. Then, various factors such as the Jahn-Teller distortion and the spin-orbital coupling of the Fe$^{2+}$ ions on the A sites and the orbital ordering and electronic itinerancy of the V$^{3+}$ ions on the B sites compete with each other to produce a complex magnetic and structural phase diagram. This phase diagram is compared to those of Fe$_{1-x}$Mn$_x$V$_2$O$_{4}$ and Mn$_{1-x}$Co$_x$V$_2$O$_{4}$ to emphasize several distinct features.
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Submitted 6 September, 2017;
originally announced September 2017.
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Landau level spectroscopy of massive Dirac fermions in single-crystalline ZrTe5 thin flakes
Authors:
Y. Jiang,
Z. L. Dun,
H. D. Zhou,
Z. Lu,
K. -W. Chen,
S. Moon,
T. Besara,
T. M. Siegrist,
R. E. Baumbach,
D. Smirnov,
Z. Jiang
Abstract:
We report infrared magneto-spectroscopy studies on thin crystals of an emerging Dirac material ZrTe5 near the intrinsic limit. The observed structure of the Landau level transitions and zero-field infrared absorption indicate a two-dimensional Dirac-like electronic structure, similar to that in graphene but with a small relativistic mass corresponding to a 9.4 meV energy gap. Measurements with cir…
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We report infrared magneto-spectroscopy studies on thin crystals of an emerging Dirac material ZrTe5 near the intrinsic limit. The observed structure of the Landau level transitions and zero-field infrared absorption indicate a two-dimensional Dirac-like electronic structure, similar to that in graphene but with a small relativistic mass corresponding to a 9.4 meV energy gap. Measurements with circularly polarized light reveal a significant electron-hole asymmetry, which leads to splitting of the Landau level transitions at high magnetic fields. Our model, based on the Bernevig-Hughes-Zhang effective Hamiltonian, quantitatively explains all observed transitions, determining the values of the Fermi velocity, Dirac mass (or gap), electron-hole asymmetry, and electron and hole g-factors.
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Submitted 23 March, 2017;
originally announced March 2017.
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Structural and magnetic properties of two branches of the Tripod Kagome Lattice family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb)
Authors:
Z. L. Dun,
J. Trinh,
M. Lee,
E. S. Choi,
K. Li,
Y. F. Hu,
Y. X. Wang,
N. Blanc,
A. P. Ramirez,
H. D. Zhou
Abstract:
We present a systematic study of the structural and magnetic properties of two branches of the rare earth Tripod Kagome Lattice (TKL) family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation \textit{A-RE}, as in \textit{MgPr} for Mg$_{2}$Pr$_{3}$Sb$_{3}$O$_{14}$), which complements our previously reported work on \textit{MgDy}, \textit{MgGd…
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We present a systematic study of the structural and magnetic properties of two branches of the rare earth Tripod Kagome Lattice (TKL) family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation \textit{A-RE}, as in \textit{MgPr} for Mg$_{2}$Pr$_{3}$Sb$_{3}$O$_{14}$), which complements our previously reported work on \textit{MgDy}, \textit{MgGd}, and \textit{MgEr} \cite{TKL}. The present susceptibility ($χ_{dc}$, $χ_{ac}$) and specific heat measurements reveal various magnetic ground states, including the non-magnetic singlet state for \textit{MgPr}, \textit{ZnPr}; long range orderings (LROs) for \textit{MgGd}, \textit{ZnGd}, \textit{MgNd}, \textit{ZnNd}, and \textit{MgYb}; a long range magnetic charge ordered state for \textit{MgDy}, \textit{ZnDy}, and potentially for \textit{MgHo}; possible spin glass states for \textit{ZnEr}, \textit{ZnHo}; the absence of spin ordering down to 80 mK for \textit{MgEr}, \textit{MgTb}, \textit{ZnTb}, and \textit{ZnYb} compounds. The ground states observed here bear both similarities as well as striking differences from the states found in the parent pyrochlore systems. In particular, while the TKLs display a greater tendency towards LRO, the lack of LRO in \textit{MgHo}, \textit{MgTb} and \textit{ZnTb} can be viewed from the standpoint of a balance among spin-spin interactions, anisotropies and non-Kramers nature of single ion state. While substituting Zn for Mg changes the chemical pressure, and subtly modifies the interaction energies for compounds with larger RE ions, this substitution introduces structural disorder and modifies the ground states for compounds with smaller RE ions (Ho, Er, Yb).
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Submitted 14 March, 2017; v1 submitted 26 October, 2016;
originally announced October 2016.
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Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4
Authors:
J. A. M. Paddison,
M. Daum,
Z. L. Dun,
G. Ehlers,
Y. Liu,
M. B. Stone,
H. D. Zhou,
M. Mourigal
Abstract:
A quantum spin liquid (QSL) is an exotic state of matter in which electrons' spins are quantum entangled over long distances, but do not show symmetry-breaking magnetic order in the zero-temperature limit. The observation of QSL states is a central aim of experimental physics, because they host collective excitations that transcend our knowledge of quantum matter; however, examples in real materia…
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A quantum spin liquid (QSL) is an exotic state of matter in which electrons' spins are quantum entangled over long distances, but do not show symmetry-breaking magnetic order in the zero-temperature limit. The observation of QSL states is a central aim of experimental physics, because they host collective excitations that transcend our knowledge of quantum matter; however, examples in real materials are scarce. Here, we report neutron-scattering measurements on YbMgGaO4, a QSL candidate in which Yb3+ ions with effective spin-1/2 occupy a triangular lattice. Our measurements reveal a continuum of magnetic excitations - the essential experimental hallmark of a QSL - at very low temperature (0.06 K). The origin of this peculiar excitation spectrum is a crucial question, because isotropic nearest-neighbor interactions do not yield a QSL ground state on the triangular lattice. Using measurements of the magnetic excitations close to the field-polarized state, we identify antiferromagnetic next-nearest-neighbor interactions in the presence of planar anisotropy as key ingredients for QSL formation in YbMgGaO4.
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Submitted 12 July, 2016;
originally announced July 2016.
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Quantum Oscillations at Integer and Fractional Landau Level Indices in ZrTe5
Authors:
W. Yu,
Y. Jiang,
J. Yang,
Z. L. Dun,
H. D. Zhou,
Z. Jiang,
P. Lu,
W. Pan
Abstract:
A three-dimensional (3D) Dirac semimetal (DS) is an analogue of graphene, but with linear energy dispersion in all (three) momentum directions.3D DSs have been a fertile playground in discovering novel quantum particles, for example Weyl fermions, in solid state systems.Many 3D DSs (e.g., ZrTe5) were theoretically predicted. We report here the results from the studies of aberration-corrected scann…
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A three-dimensional (3D) Dirac semimetal (DS) is an analogue of graphene, but with linear energy dispersion in all (three) momentum directions.3D DSs have been a fertile playground in discovering novel quantum particles, for example Weyl fermions, in solid state systems.Many 3D DSs (e.g., ZrTe5) were theoretically predicted. We report here the results from the studies of aberration-corrected scanning transmission electron microscopy and low temperature magneto-transport measurements in exfoliated ZrTe5 thin flakes.Several unique results were observed. First, an anomalous-Hall-effect-like behavior was observed around zero magnetic field (B).Second, a non-trivial Berry's phase of π was obtained from the Landau level fan diagram of the Shubnikov-de Haas oscillations in the longitudinal resistivity. Third, the longitudinal resistivity shows linear B field dependence in the quantum limit. Most surprisingly, quantum oscillations were observed at fractional Landau level indices N = 2/3 and 2/5, demonstrating strong electron-electron interactions effects in ZrTe5.
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Submitted 5 March, 2016; v1 submitted 22 February, 2016;
originally announced February 2016.
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Canted Magnetic Ground State of Quarter-Doped Manganites $R_{0.75}$Ca$_{0.25}$MnO$_3$ ($R$ = Y, Tb, Dy, Ho, and Er)
Authors:
R. Sinclair,
H. B. Cao,
V. O. Garlea,
M. Lee,
E. S. Choi,
Z. L. Dun,
S. Dong,
E. Dagotto,
H. D. Zhou
Abstract:
Polycrystalline samples of the quarter-doped manganites $R_{0.75}$Ca$_{0.25}$MnO$_3$ ($R$ = Y, Tb, Dy, Ho, and Er) were studied by X-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below $T_1$ ($\sim80$ K) and a spin glass (SG) state below $T_{SG}$ ($\sim30$ K). With increasing $R^{3+}$ ionic…
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Polycrystalline samples of the quarter-doped manganites $R_{0.75}$Ca$_{0.25}$MnO$_3$ ($R$ = Y, Tb, Dy, Ho, and Er) were studied by X-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below $T_1$ ($\sim80$ K) and a spin glass (SG) state below $T_{SG}$ ($\sim30$ K). With increasing $R^{3+}$ ionic size, both $T_1$ and $T_{SG}$ generally increase. The single crystal neutron diffraction results on Tb$_{0.75}$Ca$_{0.25}$MnO$_3$ revealed that the SG state is mainly composed of a short-range ordered version of a novel canted (i.e. noncollinear) antiferromagnetic spin state. Furthermore, calculations based on the double exchange model for quarter-doped manganites reveal that this new magnetic phase provides a transition state between the ferromagnetic state and the theoretically predicted spin-orthogonal stripe phase.
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Submitted 10 January, 2016;
originally announced January 2016.
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Ground state selection in XY pyrochlore antiferromagnets R$_{2}$Ge$_{2}$O$_{7}$ (R = Er, Yb)
Authors:
Z. L. Dun,
X. Li,
R. S. Freitas,
E. Arrighi,
C. R. Dela Cruz,
M. Lee,
E. S. Choi,
H. B. Cao,
H. J. Silverstein,
C. R. Wiebe,
J. G. Cheng,
H. D. Zhou
Abstract:
Elastic neutron scattering, ac susceptibility, and specific heat experiments on the pyrochlores Er$_{2}$Ge$_{2}$O$_{7}$ and Yb$_{2}$Ge$_{2}$O$_{7}$ show that both systems are antiferromagnetically ordered in the $Γ_5$ manifold. The ground state is a $ψ_{3}$ phase for the Er sample and a $ψ_{2}$ or $ψ_{3}$ phase for the Yb sample, which suggests "Order by Disorder"(ObD) physics. Furthermore, we uni…
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Elastic neutron scattering, ac susceptibility, and specific heat experiments on the pyrochlores Er$_{2}$Ge$_{2}$O$_{7}$ and Yb$_{2}$Ge$_{2}$O$_{7}$ show that both systems are antiferromagnetically ordered in the $Γ_5$ manifold. The ground state is a $ψ_{3}$ phase for the Er sample and a $ψ_{2}$ or $ψ_{3}$ phase for the Yb sample, which suggests "Order by Disorder"(ObD) physics. Furthermore, we unify the various magnetic ground states of all known R$_{2}$B$_{2}$O$_{7}$ (R = Er, Yb, B = Sn, Ti, Ge) compounds through the enlarged XY type exchange interaction $J_{\pm}$ under chemical pressure. The mechanism for this evolution is discussed in terms of the phase diagram proposed in the theoretical study [Wong et al., Phys. Rev. B 88, 144402, (2013)].
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Submitted 19 August, 2015; v1 submitted 18 August, 2015;
originally announced August 2015.
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Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba$_3$CoSb$_2$O$_9$
Authors:
J. Ma,
Y. Kamiya,
Tao Hong,
H. B. Cao,
G. Ehlers,
W. Tian,
C. D. Batista,
Z. L. Dun,
H. D. Zhou,
M. Matsuda
Abstract:
We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular lattice antiferromagnet Ba$_3$CoSb$_2$O$_9$. Besides confirming that the Co$^{2+}$ magnetic moments lie in the ab plane for zero magnetic field, we determine all the exchange parameters of the minimal quasi-2D spin Hamiltonian, which confirms that Ba$_3$CoSb$_2$O$_9$ is an almost perfect realization of…
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We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular lattice antiferromagnet Ba$_3$CoSb$_2$O$_9$. Besides confirming that the Co$^{2+}$ magnetic moments lie in the ab plane for zero magnetic field, we determine all the exchange parameters of the minimal quasi-2D spin Hamiltonian, which confirms that Ba$_3$CoSb$_2$O$_9$ is an almost perfect realization of the paradigmatic model of frustrated quantum magnetism. A comparison with linear and nonlinear spin-wave theory reveals that quantum fluctuations induce a strong downward renormalization of the magnon dispersion.
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Submitted 26 February, 2016; v1 submitted 21 July, 2015;
originally announced July 2015.
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Strong competition between orbital-ordering and itinerancy in a frustrated spinel vanadate
Authors:
J. Ma,
J. H. Lee,
S. E. Hahn,
Tao Hong,
H. B. Cao,
A. A. Aczel,
Z. L. Dun,
M. B. Stone,
W. Tian,
Y. Qiu,
J. R. D. Copley,
H. D. Zhou,
R. S. Fishman,
M. Matsuda
Abstract:
The crossover from localized- to itinerant-electron behavior is associated with many intriguing phenomena in condensed-matter physics. In this paper, we investigate the crossover from localized to itinerant regimes in the spinel system Mn$_{1-x}$Co$_x$V$_2$O$_4$. At low Co doping, orbital order (OO) of the localized electrons on the V3+ ions suppresses magnetic frustration by triggering a tetragon…
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The crossover from localized- to itinerant-electron behavior is associated with many intriguing phenomena in condensed-matter physics. In this paper, we investigate the crossover from localized to itinerant regimes in the spinel system Mn$_{1-x}$Co$_x$V$_2$O$_4$. At low Co doping, orbital order (OO) of the localized electrons on the V3+ ions suppresses magnetic frustration by triggering a tetragonal distortion. With Co doping, electronic itinerancy melts the OO and suppresses the structural phase transition while the reduced spin-lattice coupling produces magnetic frustration. Neutron scattering measurements and first-principles-guided spin models reveal that the non-collinear state at high Co doping is produced by weakened local anisotropy and enhanced Co-V spin interactions.
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Submitted 16 July, 2015; v1 submitted 15 July, 2014;
originally announced July 2014.
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Magnetic Phase Transition in the Low Dimensional Compound BaMn2Si2O7
Authors:
J. Ma,
C. D. Dela Cruz,
T. Hong,
W. Tian,
A. A. Aczel,
Songxue Chi,
J. -Q. Yan,
Z. L. Dun,
H. D. Zhou,
M. Matsuda
Abstract:
The structural and magnetic properties of BaMn2Si2O7 have been investigated. The magnetic susceptibility and specific heat, measured using single crystals, suggest that the quasi-one-dimensional magnetism originating from the loosely coupled Mn2+ chain carrying S=5/2 is present at high temperatures, which is similar to the other quasi-one-dimensional barium silicates, BaM2Si2O7 (M: Cu and Co). The…
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The structural and magnetic properties of BaMn2Si2O7 have been investigated. The magnetic susceptibility and specific heat, measured using single crystals, suggest that the quasi-one-dimensional magnetism originating from the loosely coupled Mn2+ chain carrying S=5/2 is present at high temperatures, which is similar to the other quasi-one-dimensional barium silicates, BaM2Si2O7 (M: Cu and Co). The Neel temperature (TN=26 K) is high compared to the magnetic interaction along the chain (J = -6 K). The neutron powder diffraction study has revealed that the magnetic structure is long-ranged with antiferromagnetic arrangement along the chain (c) direction and ferromagnetic arrangement along the a and b axes. The detailed structural analysis suggests that the interchain interaction via Mn-O-Mn bond along the a axis is relatively large, which makes the system behave more two-dimensionally in the ac plane and enhances TN.
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Submitted 7 October, 2013; v1 submitted 16 September, 2013;
originally announced September 2013.