scholarly journals Giant isotropic magneto-thermal conductivity of metallic spin liquid candidate Pr2Ir2O7 with quantum criticality

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. M. Ni ◽  
Y. Y. Huang ◽  
E. J. Cheng ◽  
Y. J. Yu ◽  
B. L. Pan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Magnetic Monopoles ◽  
Quantum Criticality ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Zero Field ◽  
Spin Liquids ◽  
Quantum Critical

AbstractSpin liquids are exotic states with no spontaneous symmetry breaking down to zero-temperature because of the highly entangled and fluctuating spins in frustrated systems. Exotic excitations like magnetic monopoles, visons, and photons may emerge from quantum spin ice states, a special kind of spin liquids in pyrochlore lattices. These materials usually are insulators, with an exception of the pyrochlore iridate Pr2Ir2O7, which was proposed as a metallic spin liquid located at a zero-field quantum critical point. Here we report the ultralow-temperature thermal conductivity measurements on Pr2Ir2O7. The Wiedemann–Franz law is verified at high fields and inferred at zero field, suggesting no breakdown of Landau quasiparticles at the quantum critical point, and the absence of mobile fermionic excitations. This result puts strong constraints on the description of the quantum criticality in Pr2Ir2O7. Unexpectedly, although the specific heats are anisotropic with respect to magnetic field directions, the thermal conductivities display the giant but isotropic response. This indicates that quadrupolar interactions and quantum fluctuations are important, which will help determine the true ground state of this material.

scholarly journals Spin liquid and ferroelectricity close to a quantum critical point in PbCuTe2O6

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Christian Thurn ◽  
Paul Eibisch ◽  
Arif Ata ◽  
Maximilian Winkler ◽  
Peter Lunkenheimer ◽  
...  
Keyword(s):  
Quantum Critical Point ◽  
Quantum Fluctuations ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Spin Liquids ◽  
Range Magnetic Order ◽  
Powder Samples ◽  
Quantum Critical ◽  
Quantum Spin Liquid ◽  
Long Range Magnetic Order

AbstractGeometrical frustration among interacting spins combined with strong quantum fluctuations destabilize long-range magnetic order in favor of more exotic states such as spin liquids. By following this guiding principle, a number of spin liquid candidate systems were identified in quasi-two-dimensional (quasi-2D) systems. For 3D, however, the situation is less favorable as quantum fluctuations are reduced and competing states become more relevant. Here we report a comprehensive study of thermodynamic, magnetic and dielectric properties on single crystalline and pressed-powder samples of PbCuTe2O6, a candidate material for a 3D frustrated quantum spin liquid featuring a hyperkagome lattice. Whereas the low-temperature properties of the powder samples are consistent with the recently proposed quantum spin liquid state, an even more exotic behavior is revealed for the single crystals. These crystals show ferroelectric order at TFE ≈ 1 K, accompanied by strong lattice distortions, and a modified magnetic response—still consistent with a quantum spin liquid—but with clear indications for quantum critical behavior.

scholarly journals Thermal Conductivity through the Quantum Critical Point inYbRh2Si2at Very Low Temperature

2015 ◽  
Vol 115 (4) ◽  
Author(s):  
M. Taupin ◽  
G. Knebel ◽  
T. D. Matsuda ◽  
G. Lapertot ◽  
Y. Machida ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Quantum Critical ◽  
Very Low Temperature

scholarly journals Entanglement signatures of emergent Dirac fermions: Kagome spin liquid and quantum criticality

2018 ◽  
Vol 4 (11) ◽  
pp. eaat5535 ◽  
Author(s):  
Wei Zhu ◽  
Xiao Chen ◽  
Yin-Chen He ◽  
William Witczak-Krempa
Keyword(s):  
Entanglement Entropy ◽  
Quantum Critical Point ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Dirac Fermions ◽  
Spin Liquids ◽  
Density Matrix Renormalization ◽  
Dirac Semimetal ◽  
A Charge ◽  
Aharonov Bohm

Quantum spin liquids (QSLs) are exotic phases of matter that host fractionalized excitations. It is difficult for local probes to characterize QSL, whereas quantum entanglement can serve as a powerful diagnostic tool due to its nonlocality. The kagome antiferromagnetic Heisenberg model is one of the most studied and experimentally relevant models for QSL, but its solution remains under debate. Here, we perform a numerical Aharonov-Bohm experiment on this model and uncover universal features of the entanglement entropy. By means of the density matrix renormalization group, we reveal the entanglement signatures of emergent Dirac spinons, which are the fractionalized excitations of the QSL. This scheme provides qualitative insights into the nature of kagome QSL and can be used to study other quantum states of matter. As a concrete example, we also benchmark our methods on an interacting quantum critical point between a Dirac semimetal and a charge-ordered phase.

scholarly journals Thermal conductivity at a disordered quantum critical point

2016 ◽  
Vol 2016 (4) ◽  
pp. 1-24 ◽  
Author(s):  
Sean A. Hartnoll ◽  
David M. Ramirez ◽  
Jorge E. Santos
Keyword(s):  
Thermal Conductivity ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Quantum Critical

scholarly journals Zero-field quantum critical point in Ce0.91Yb0.09CoIn5

2018 ◽  
Vol 97 (18) ◽  
Author(s):  
Y. P. Singh ◽  
R. B. Adhikari ◽  
D. J. Haney ◽  
B. D. White ◽  
M. B. Maple ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Zero Field ◽  
Quantum Critical

scholarly journals Linear resistivity and Sachdev-Ye-Kitaev (SYK) spin liquid behavior in a quantum critical metal with spin-1/2 fermions

2020 ◽  
Vol 117 (31) ◽  
pp. 18341-18346 ◽  
Author(s):  
Peter Cha ◽  
Nils Wentzell ◽  
Olivier Parcollet ◽  
Antoine Georges ◽  
Eun-Ah Kim
Keyword(s):  
Fermi Liquid ◽  
Spin Dynamics ◽  
Quantum Critical Point ◽  
Quantum Spin ◽  
Spin Interaction ◽  
Spin Liquid ◽  
Spin Glass Phase ◽  
Scattering Rate ◽  
Liquid Behavior ◽  
Quantum Critical

“Strange metals” with resistivity depending linearly on temperature T down to low T have been a long-standing puzzle in condensed matter physics. Here, we consider a lattice model of itinerant spin-1/2fermions interacting via onsite Hubbard interaction and random infinite-ranged spin–spin interaction. We show that the quantum critical point associated with the melting of the spin-glass phase by charge fluctuations displays non-Fermi liquid behavior, with local spin dynamics identical to that of the Sachdev-Ye-Kitaev family of models. This extends the quantum spin liquid dynamics previously established in the large-M limit ofSU(M)symmetric models to models with physicalSU(2)spin-1/2electrons. Remarkably, the quantum critical regime also features a Planckian linear-T resistivity associated with a T-linear scattering rate and a frequency dependence of the electronic self-energy consistent with the marginal Fermi liquid phenomenology.

scholarly journals Itinerant quantum critical point with fermion pockets and hotspots

2019 ◽  
Vol 116 (34) ◽  
pp. 16760-16767 ◽  
Author(s):  
Zi Hong Liu ◽  
Gaopei Pan ◽  
Xiao Yan Xu ◽  
Kai Sun ◽  
Zi Yang Meng
Keyword(s):  
Critical Point ◽  
Quantum Monte Carlo ◽  
Fermi Liquid ◽  
Large Scale ◽  
Quantum Critical Point ◽  
Quantum Criticality ◽  
Spin Fluctuations ◽  
Square Lattice ◽  
Quantum Critical ◽  
Antiferromagnetic Spin

Metallic quantum criticality is among the central themes in the understanding of correlated electronic systems, and converging results between analytical and numerical approaches are still under review. In this work, we develop a state-of-the-art large-scale quantum Monte Carlo simulation technique and systematically investigate the itinerant quantum critical point on a 2D square lattice with antiferromagnetic spin fluctuations at wavevector Q=(π,π)—a problem that resembles the Fermi surface setup and low-energy antiferromagnetic fluctuations in high-Tc cuprates and other critical metals, which might be relevant to their non–Fermi-liquid behaviors. System sizes of 60×60×320 (L×L×Lτ) are comfortably accessed, and the quantum critical scaling behaviors are revealed with unprecedented high precision. We found that the antiferromagnetic spin fluctuations introduce effective interactions among fermions and the fermions in return render the bare bosonic critical point into a different universality, different from both the bare Ising universality class and the Hertz–Mills–Moriya RPA prediction. At the quantum critical point, a finite anomalous dimension η∼0.125 is observed in the bosonic propagator, and fermions at hotspots evolve into a non-Fermi liquid. In the antiferromagnetically ordered metallic phase, fermion pockets are observed as the energy gap opens up at the hotspots. These results bridge the recent theoretical and numerical developments in metallic quantum criticality and can serve as the stepping stone toward final understanding of the 2D correlated fermions interacting with gapless critical excitations.

scholarly journals μSR and NMR study on quantum critical point in quantum spin ladder (CH3)2CHNH3Cu(ClxBr1−x)3

2010 ◽  
Vol 200 (2) ◽  
pp. 022036 ◽  
Author(s):  
S Nakajima ◽  
T Goto ◽  
T Suzuki ◽  
I Watanabe ◽  
H Manaka ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Quantum Spin ◽  
Spin Ladder ◽  
Nmr Study ◽  
Quantum Critical

scholarly journals Spin liquid close to a quantum critical point in Na4Ir3O8

2013 ◽  
Vol 88 (22) ◽  
Author(s):  
Yogesh Singh ◽  
Y. Tokiwa ◽  
J. Dong ◽  
P. Gegenwart
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Spin Liquid ◽  
Quantum Critical
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