scholarly journals Multiple quantum phase transitions of different nature in the topological kagome magnet Co3Sn2−xInxS2

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Z. Guguchia ◽  
H. Zhou ◽  
C. N. Wang ◽  
J.-X. Yin ◽  
C. Mielke ◽  
...  
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transitions ◽  
Muon Spin ◽  
Quantum Critical Point ◽  
Quantum Phase ◽  
Muon Spin Rotation ◽  
Multiple Quantum ◽  
Zero Temperature ◽  
In Doping ◽  
Out Of Plane

AbstractThe exploration of topological electronic phases that result from strong electronic correlations is a frontier in condensed matter physics. One class of systems that is currently emerging as a platform for such studies are so-called kagome magnets based on transition metals. Using muon spin-rotation, we explore magnetic correlations in the kagome magnet Co3Sn2−xInxS2 as a function of In-doping, providing putative evidence for an intriguing incommensurate helimagnetic (HM) state. Our results show that, while the undoped sample exhibits an out-of-plane ferromagnetic (FM) ground state, at 5% of In-doping the system enters a state in which FM and in-plane antiferromagnetic (AFM) phases coexist. At higher doping, a HM state emerges and becomes dominant at the critical doping level of only xcr,1 ≃ 0.3. This indicates a zero temperature first order quantum phase transition from the FM, through a mixed state, to a helical phase at xcr,1. In addition, at xcr,2 ≃ 1, a zero temperature second order phase transition from helical to paramagnetic phase is observed, evidencing a HM quantum critical point (QCP) in the phase diagram of the topological magnet Co3Sn2−xInxS2. The observed diversity of interactions in the magnetic kagome lattice drives non-monotonous variations of the topological Hall response of this system.

scholarly journals Size dependent nature of the magnetic-field driven superconductor-to-insulator quantum-phase transitions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaofu Zhang ◽  
Adriana E. Lita ◽  
Huanlong Liu ◽  
Varun B. Verma ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quantum Phase Transition ◽  
Quantum Phase Transitions ◽  
Temperature Limit ◽  
Quantum Phase ◽  
Zero Temperature ◽  
Size Dependent ◽  
Open Question ◽  
The Magnetic Field

AbstractThe nature of the magnetic-field driven superconductor-to-insulator quantum-phase transition in two-dimensional systems at zero temperature has been under debate since the 1980s, and became even more controversial after the observation of a quantum-Griffiths singularity. Whether it is induced by quantum fluctuations of the superconducting phase and the localization of Cooper pairs, or is directly driven by depairing of these pairs, remains an open question. We herein experimentally demonstrate that in weakly-pinning systems and in the limit of infinitely wide films, a sequential superconductor-to-Bose insulator-to-Fermi insulator quantum-phase transition takes place. By limiting their size to smaller than the effective penetration depth, however, the vortex interaction alters, and the superconducting state re-enters the Bose-insulating state. As a consequence, one observes a direct superconductor-to-Fermi insulator in the zero-temperature limit. In narrow films, the associated critical-exponent products diverge along the corresponding phase boundaries with increasing magnetic field, which is a hallmark of the quantum-Griffiths singularity.

scholarly journals Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions

2016 ◽  
Vol 79 (9) ◽  
pp. 094503 ◽  
Author(s):  
Z F Weng ◽  
M Smidman ◽  
L Jiao ◽  
Xin Lu ◽  
H Q Yuan
Keyword(s):  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Heavy Fermions ◽  
Quantum Phase ◽  
Multiple Quantum

scholarly journals INTERPLAY BETWEEN QUANTUM PHASE TRANSITIONS AND THE BEHAVIOR OF QUANTUM CORRELATIONS AT FINITE TEMPERATURES

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345032 ◽  
Author(s):  
T. WERLANG ◽  
G. A. P. RIBEIRO ◽  
GUSTAVO RIGOLIN
Keyword(s):  
Phase Transitions ◽  
Critical Point ◽  
Thermodynamic Limit ◽  
Quantum Discord ◽  
Quantum Phase Transitions ◽  
Quantum Correlations ◽  
Infinite Chain ◽  
Quantum Phase ◽  
Absolute Zero ◽  
Zero Temperature

We review the main results and ideas showing that quantum correlations at finite temperatures (T), in particular quantum discord, are useful tools in characterizing quantum phase transitions (QPT) that only occur, in principle, at the unattainable absolute zero temperature. We first review some interesting results about the behavior of thermal quantum discord for small spin-1/2 chains and show that they already give us important hints of the infinite chain behavior. We then study in detail and in the thermodynamic limit (infinite chains) the thermal quantum correlations for the XXZ and XY models, where one can clearly appreciate that the behavior of thermal quantum discord at finite T is a useful tool to spotlight the critical point of a QPT.

scholarly journals Muonium atoms in liquid and solid neopentane

1983 ◽  
Vol 61 (4) ◽  
pp. 671-674 ◽  
Author(s):  
B. W. Ng ◽  
J. M. Stadlbauer ◽  
Y. C. Jean ◽  
D. C. Walker
Keyword(s):  
Phase Transition ◽  
Spin Relaxation ◽  
Formation Mechanism ◽  
Solid Phase ◽  
Muon Spin ◽  
Spin Rotation ◽  
Muon Spin Rotation ◽  
Current Interest ◽  
Solid Phase Transition

Relatively long-lived muonium atoms have been observed in neopentane (dimethylpropane). The yields of all muon states are found to be essentially the same in liquid and solid neopentane and the same as those in water. These results have bearings on three matters of current interest in muonium chemistry: the origin of the "background" spin relaxation; the formation mechanism; and the change in yields at the liquid–solid phase transition. These data were obtained by the μSR technique (muon spin rotation) at the TRIUMF accelerator.

scholarly journals SCALING OF VON NEUMANN ENTROPY AT THE ANDERSON TRANSITION

2010 ◽  
Vol 24 (12n13) ◽  
pp. 1823-1840 ◽  
Author(s):  
Sudip Chakravarty
Keyword(s):  
Phase Transition ◽  
Wave Function ◽  
Phase Transitions ◽  
Ground State ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Tuning Parameter ◽  
Von Neumann Entropy ◽  
Von Neumann ◽  
Anderson Transition

Extensive body of work has shown that for the model of a non-interacting electron in a random potential there is a quantum critical point for dimensions greater than two — a metal–insulator transition. This model also plays an important role in the plateau-to-plateu transition in the integer quantum Hall effect, which is also correctly captured by a scaling theory. Yet, in neither of these cases the ground state energy shows any non-analyticity as a function of a suitable tuning parameter, typically considered to be a hallmark of a quantum phase transition, similar to the non-analyticity of the free energy in a classical phase transition. Here we show that von Neumann entropy (entanglement entropy) is non-analytic at these phase transitions and can track the fundamental changes in the internal correlations of the ground state wave function. In particular, it summarizes the spatially wildly fluctuating intensities of the wave function close to the criticality of the Anderson transition. It is likely that all quantum phase transitions can be similarly described.

scholarly journals Superconductor–insulator transition in capacitively coupled superconducting nanowires

2020 ◽  
Vol 11 ◽  
pp. 1402-1408
Author(s):  
Alex Latyshev ◽  
Andrew G Semenov ◽  
Andrei D Zaikin
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Superconducting Nanowires ◽  
Capacitively Coupled ◽  
Renormalization Group Equations ◽  
Mutual Capacitance ◽  
Quantum Phase Slips ◽  
Insulator Phase Transition ◽  
Phase Slips

We investigate superconductor–insulator quantum phase transitions in ultrathin capacitively coupled superconducting nanowires with proliferating quantum phase slips. We derive a set of coupled Berezinskii–Kosterlitz–Thouless-like renormalization group equations demonstrating that interaction between quantum phase slips in one of the wires gets modified due to the effect of plasma modes propagating in another wire. As a result, the superconductor–insulator phase transition in each of the wires is controlled not only by its own parameters but also by those of the neighboring wire as well as by mutual capacitance. We argue that superconducting nanowires with properly chosen parameters may turn insulating once they are brought sufficiently close to each other.

scholarly journals Classical and Quantum Signatures of Quantum Phase Transitions in a (Pseudo) Relativistic Many-Body System

2020 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Maximilian Nitsch ◽  
Benjamin Geiger ◽  
Klaus Richter ◽  
Juan-Diego Urbina
Keyword(s):  
Phase Transition ◽  
Quantum Phase Transition ◽  
Quantum Phase Transitions ◽  
Mean Field ◽  
Finite Size ◽  
Quantum Phase ◽  
Effective Model ◽  
Field Analysis ◽  
Many Body ◽  
Linear Dispersion

We identify a (pseudo) relativistic spin-dependent analogue of the celebrated quantum phase transition driven by the formation of a bright soliton in attractive one-dimensional bosonic gases. In this new scenario, due to the simultaneous existence of the linear dispersion and the bosonic nature of the system, special care must be taken with the choice of energy region where the transition takes place. Still, due to a crucial adiabatic separation of scales, and identified through extensive numerical diagonalization, a suitable effective model describing the transition is found. The corresponding mean-field analysis based on this effective model provides accurate predictions for the location of the quantum phase transition when compared against extensive numerical simulations. Furthermore, we numerically investigate the dynamical exponents characterizing the approach from its finite-size precursors to the sharp quantum phase transition in the thermodynamic limit.

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