scholarly journals Magnetic field-induced intermediate quantum spin liquid with a spinon Fermi surface

2019 ◽  
Vol 116 (25) ◽  
pp. 12199-12203 ◽  
Author(s):  
Niravkumar D. Patel ◽  
Nandini Trivedi
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Intermediate Phase ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Spin Correlations ◽  
Density Matrix Renormalization ◽  
Static Spin ◽  
Kitaev Model ◽  
Quantum Spin Liquid

The Kitaev model with an applied magnetic field in the H∥[111] direction shows two transitions: from a nonabelian gapped quantum spin liquid (QSL) to a gapless QSL at Hc1≃0.2K and a second transition at a higher field Hc2≃0.35K to a gapped partially polarized phase, where K is the strength of the Kitaev exchange interaction. We identify the intermediate phase to be a gapless U(1) QSL and determine the spin structure function S(k) and the Fermi surface ϵFS(k) of the gapless spinons using the density matrix renormalization group (DMRG) method for large honeycomb clusters. Further calculations of static spin-spin correlations, magnetization, spin susceptibility, and finite temperature-specific heat and entropy corroborate the gapped and gapless nature of the different field-dependent phases. In the intermediate phase, the spin-spin correlations decay as a power law with distance, indicative of a gapless phase.

scholarly journals Superconductivity in the doped quantum spin liquid on the triangular lattice

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Hong-Chen Jiang
Keyword(s):  
Large Scale ◽  
High Temperature Superconductivity ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Electron Pairs ◽  
Pair Correlations ◽  
Spin Correlations ◽  
Definitive Evidence ◽  
Density Matrix Renormalization ◽  
Quantum Spin Liquid

AbstractBroad interest in quantum spin liquid (QSL) phases was triggered by the notion that they can be viewed as insulating phases with preexisting electron pairs, such that upon light doping they might automatically yield high temperature superconductivity. Yet despite intense experimental and numerical efforts, definitive evidence showing that doping QSLs leads to superconductivity has been lacking. We address the problem of a lightly doped QSL through a large-scale density-matrix renormalization group study of the t-J model on finite-circumference triangular cylinders with a small but nonzero concentration of doped holes. We provide direct evidences that doping QSL can naturally give rise to d-wave superconductivity. Specifically, we find power-law superconducting correlations with a Luttinger exponent, Ksc ≈ 1, which is consistent with a strongly diverging superconducting susceptibility, $${\chi }_{sc} \,\sim\, {T}^{-(2\,-\,{K}_{sc})}$$ χ s c ~ T − ( 2 − K s c ) as the temperature T → 0. The spin–spin correlations—as in the undoped QSL state—fall exponentially which suggests that the superconducting pair-pair correlations evolve smoothly from the insulating parent state.

scholarly journals Эволюция квантования Ландау спектра спинонных пар в слабом мотовском диэлектрике La-=SUB=-0.15-=/SUB=-Sm-=SUB=-0.85-=/SUB=-MnO-=SUB=-3+delta-=/SUB=- со спинонной поверхностью Ферми с ростом температуры и напряженности магнитного поля

2021 ◽  
Vol 63 (5) ◽  
pp. 639
Author(s):  
Ф.Н. Буханько ◽  
А.Ф. Буханько
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Quantum Oscillations ◽  
Temperature Range ◽  
Complete Filling ◽  
Weak Magnetic Fields ◽  
Temperature Dependences ◽  
Quantum Spin Liquid

Measurements of the magnetization temperature dependences of La0.15Sm0.85MnO3+δ in the temperature range 4.2 - 100 K revealed a threshold magnetization feature near the temperature Td 50 K, associated with the existence of a small pseudogap Δe in the electron spectrum, which is characteristic of a weak Mott dielectric. An increase in the strength H of the external magnetic field leads to suppression of the dielectric pseudogap Δe, an increase in the density of states of free charge/ spin carriers at EF, and transformation of the charge/spin density waves fragments. A quantization of the pairs spectrum of the low-energy magnetic excitations of a Z2 quantum spin liquid in the form of spinon-gauge field composite quasiparticles was found in the temperature range 4.2 - 12 K. Formation of a continuous spectrum of the quantum spin liquid excitations in the regime of “weak magnetic fields” Н = 100 Oe, 350 Oe, 1 kOe is explained within the framework of the Landau quantization models of the spectrum of composite quasiparticles with fractional values of the factor ν filling of three overlapping Landau zones.. In the regime of a “strong external magnetic field” H = 3.5 kOe, the new quantum oscillations of the temperature dependences of the magnetization of an incompressible spinon liquid were founded in the form of three narrow steps (plateaus) corresponding to the complete filling of non-overlapping Landau zones with integer values of the filling factor by spinons.

scholarly journals Evidence for a spinon Fermi surface in the triangular S=1 quantum spin liquid Ba3NiSb2O9

2017 ◽  
Vol 95 (6) ◽  
Author(s):  
B. Fåk ◽  
S. Bieri ◽  
E. Canévet ◽  
L. Messio ◽  
C. Payen ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Quantum Spin Liquid

scholarly journals Identification of a Kitaev quantum spin liquid by magnetic field angle dependence

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Kyusung Hwang ◽  
Ara Go ◽  
Ji Heon Seong ◽  
Takasada Shibauchi ◽  
Eun-Gook Moon
Keyword(s):  
Magnetic Field ◽  
Quantum Spin ◽  
Majorana Fermion ◽  
Spin Liquid ◽  
Majorana Fermions ◽  
Angle Dependence ◽  
Topological Quantum ◽  
Quantum Science ◽  
Quantum Spin Liquid ◽  
Critical Lines

AbstractQuantum spin liquids realize massive entanglement and fractional quasiparticles from localized spins, proposed as an avenue for quantum science and technology. In particular, topological quantum computations are suggested in the non-abelian phase of Kitaev quantum spin liquid with Majorana fermions, and detection of Majorana fermions is one of the most outstanding problems in modern condensed matter physics. Here, we propose a concrete way to identify the non-abelian Kitaev quantum spin liquid by magnetic field angle dependence. Topologically protected critical lines exist on a plane of magnetic field angles, and their shapes are determined by microscopic spin interactions. A chirality operator plays a key role in demonstrating microscopic dependences of the critical lines. We also show that the chirality operator can be used to evaluate topological properties of the non-abelian Kitaev quantum spin liquid without relying on Majorana fermion descriptions. Experimental criteria for the non-abelian spin liquid state are provided for future experiments.

scholarly journals Magnetic Field Induced Quantum Spin Liquid in the Two Coupled Trillium Lattices of K2Ni2(SO4)3

2021 ◽  
Vol 127 (15) ◽  
Author(s):  
Ivica Živković ◽  
Virgile Favre ◽  
Catalina Salazar Mejia ◽  
Harald O. Jeschke ◽  
Arnaud Magrez ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Quantum Spin Liquid
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