Quantum Spin Liquid Emerging from Antiferromagnetic Order by Introducing Disorder

Furukawa, T.; Miyagawa, Kazuya; Itou, Tetsuaki; Ito, Miho; Taniguchi, Hiromi; Saito, Mitsuhiro; Iguchi, Satoshi; Sasaki, T.; Kanoda, K.

doi:10.1103/physrevlett.115.077001

Cited by 76 publications

(70 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, a general consensus in interpreting the T dependence of 1/T 1 in the SL materials is still lacking and little progress has been made in evolving a more generic and comprehensive framework. This is due to the unavailability of many model SL materials and experimental challenges in interpreting the implications of various subtle theoretical scenarios [1,26,30]. Furthermore, one would expect a T-independent behavior of 1/T 1 T in the case of a spin liquid with a spinon Fermi surface and 1/T 1 T should drop exponentially in the case of gapped SL [1,4,39,[59][60][61]65].…”

Section: +mentioning

confidence: 99%

“…The power law behavior of C m and 1/T 1 with decreasing temperature down to 100 mK infer gapless excitations consistent with χ int and suggest a quantum spin liquid state. The effect of site dilution, defect, and disorder in frustrated quantum magnets have been discussed in the context of novel magnetism such as spin liquids recently [19,30,31,64]. The absence of spin freezing and no spin gap down to 50 mK in SGCO suggest that the low energy excitations might be mediated by deconfined spinons, which is generic to a gapless QSL state in frustrated quantum magnets.…”

Section: +mentioning

confidence: 99%

“…Among the frustrated magnets, the edge-shared triangular lattice AFM with S = 1/2 offers the simplest archetype for QSL and to test theoretical models in other relatively complex lattices [13,26,28,29]. Furtheremore, the role of intersite distribution or disorder in stabilizing a QSL state in frustrated quantum magnets has recently been suggested [19,30,31,49].In view of the vastly evolving field of frustrated magnetism, significant attention has recently been paid to the growth and design of new quantum magnets which could epitomize as model materials for hosting exotic excitations pertinent to novel states and to test theoretical conjectures [1, 4,5, 9]. In the quest for novel states in frustrated magnets with low spin where inherent quantum effects lead to emergent phenomena, we synthesize and investigate an inorganic S = 1/2 antiferromagnet Sc 2 Ga 2 CuO 7 (henceforth SGCO).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Spin liquid state in the disordered triangular latticeSc2Ga2CuO7revealed by NMR

et al. 2016

View full text Add to dashboard Cite

We present microscopic magnetic properties of a two dimensional triangular lattice Sc 2 Ga 2 CuO 7 , consisting of single and double triangular Cu planes. An antiferromagnetic (AFM) exchange interaction J/k B ≈ 35 K between Cu 2+ (S = 1/2) spins in the triangular bi-plane is obtained from the analysis of intrinsic magnetic susceptibility data. The intrinsic magnetic susceptibility, extracted from 71 Ga NMR shift data, displays the presence of AFM short range spin correlations and remains finite down to 50 mK suggesting a nonsinglet ground state. The nuclear spin-lattice relaxation rate (1/T 1 ) reveals a slowing down of Cu 2+ spin fluctuations with decreasing T down to 100 mK. Magnetic specific heat (Cm) and 1/T 1 exhibit a power law behavior at low temperatures implying gapless nature of the spin excitation spectrum. Absence of long range magnetic ordering down to ∼ J/700, nonzero spin susceptibility at low T , and power law behavior of Cm and 1/T 1 suggest a gapless quantum spin liquid (QSL) state. Our results demonstrate that persistent spin dynamics induced by frustration maintain a quantum-disordered state at T → 0 in this triangular lattice antiferromagnet. This suggests that the low energy modes are dominated by spinon excitations in the QSL state due to randomness engendered by disorder and frustration.PACS numbers: 75.40. Cx,75.10.Kt, 76.60.Es, 74.40.Kb Collective excitations, frustration, and quantum fluctuations are key ingredients in driving novel ground state properties of correlated electron systems. Geometrically frustrated magnets harbor exotic physical phenomena such as spin glass, quantum spin liquid (QSL), spin ice, and superconductivity [1][2][3][4][5]. The incompatibility of magnetic exchange interactions in achieving minimum energy yields degenerate ground states and the associated strong quantum fluctuations prevent the spin system from undergoing a symmetry breaking phase transition [1,[3][4][5][6][7][8][9]. The experimental realization of novel states such as QSL in real materials is an exciting prospect in answering some of the key issues in condensed matter and set an enduring theme following Anderson's resonance valence bond theory [10, 11]. The most prominent QSL candidates reported so far are S = 1/2 kagomé lattices ZnCu 3 (OH) [4,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][32][33][34][35][36][37]. The frustrated quantum magnets are proposed to host emergent fractional excitations in the gapless QSL state, which is reflected as power law behavior in bulk and microscopic observables [1,[38][39][40][41][42][43][44]. Recently, the observation of intriguing magnetic properties in Ba 3 TSb 2 O 9 (T=Cu, Co, Ni) and 5d iridates has rekindled enormous research activities in quantum materials in the context of emergent quantum states [1, 2,23,[45][46][47][48][49][50][51]. Among the frustrated magnets, the edge-shared triangular lattice AFM with S = 1/2 offers the simplest archetype for QSL and to test theoretical models in other relatively complex lat...

show abstract

Section: +mentioning

confidence: 99%

Section: +mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Spin liquid state in the disordered triangular latticeSc2Ga2CuO7revealed by NMR

et al. 2016

View full text Add to dashboard Cite

show abstract

“…There is some evidence that weak disorder in presence of strong interactions [3][4][5][6][7] as well as strong disorder in presence of weak interactions [8] compete with each other, but the question of strong disorder in presence of strong repulsion remains unresolved. This is not merely an issue of theoretical interest, since the complex interplay of electronic interactions and disorder in twodimensional (2D) materials is often crucial to understanding novel phenomena [9][10][11][12][13][14] beyond the standard paradigm of Fermi liquid and BCS superconductivity.A prototype of strongly interacting electronic systems is the cuprate high T c superconductors (HTSC), which are antiferromagnetic Mott insulators at half-filling (one particle per site) and show d-wave superconductivity for a range of doping. In this paper, we will consider the effect of strong disorder on the strongly interacting d-wave superconducting (SC) state proximal to the Mott insulator.…”

mentioning

confidence: 99%

Effects of strong disorder in strongly correlated superconductors

2017

View full text Add to dashboard Cite

We investigate the effect of strong disorder on a system with strong electronic repulsion. In absence of disorder, the system has a d-wave superconducting ground-state with strong non-BCS features due to its proximity to a Mott insulator. We find that, while strong correlations make superconductivity in this system immune to weak disorder, superconductivity is destroyed efficiently when disorder strength is comparable to the effective bandwidth. The suppression of charge motion in regions of strong potential fluctuation leads to formation of Mott insulating patches, which anchor a larger non-superconducting region around them. The system thus breaks into islands of Mott insulating and superconducting regions, with Anderson insulating regions occurring along the boundary of these regions. Thus, electronic correlation and disorder, when both are strong, aid each other in destroying superconductivity, in contrast to their competition at weak disorder. Our results shed light on why Zinc impurities are efficient in destroying superconductivity in cuprates, even though it is robust to weaker impurities.Strong inter-particle interactions and strong inhomogeneous potentials both tend to localize fermions. Strong repulsion can result in complete suppression of charge motion at commensurate filling, leading to a Mott insulator [1], while strong disorder, causes decoherence of fermions triggering formation of Anderson insulators [2]. There is some evidence that weak disorder in presence of strong interactions [3][4][5][6][7] as well as strong disorder in presence of weak interactions [8] compete with each other, but the question of strong disorder in presence of strong repulsion remains unresolved. This is not merely an issue of theoretical interest, since the complex interplay of electronic interactions and disorder in twodimensional (2D) materials is often crucial to understanding novel phenomena [9][10][11][12][13][14] beyond the standard paradigm of Fermi liquid and BCS superconductivity.A prototype of strongly interacting electronic systems is the cuprate high T c superconductors (HTSC), which are antiferromagnetic Mott insulators at half-filling (one particle per site) and show d-wave superconductivity for a range of doping. In this paper, we will consider the effect of strong disorder on the strongly interacting d-wave superconducting (SC) state proximal to the Mott insulator. Our key findings are: (i) While the presence of strong correlations makes superconductivity robust to weak disorder, at large disorder comparable to bandwidth, superconductivity is rapidly suppressed. (ii) At large disorder, Mott insulating patches anchor a surrounding region akin to Anderson insulator. With increasing disorder strength, these islands grow at the expense of local superconductivity. Thus at large disorder, strong correlation and strong potential fluctuations help each other in bringing about the sudden death of superconductivity. The three distinct regions leave clear signatures in the local density of states. Our results shed ...

show abstract

“…Also, the realization of a QSL state for Ba 3 IrTi 2 O 9 [16], containing a diluted triangular lattice, and Ba 3 YIr 2 O 9 (high pressure cubic phase) [17], possibly suggests the importance of further neighbor interactions and/or deviations from the Heisenberg model. Recent experimental/theoretical results suggest that disorder might even drive the QSL state [18,19]. The unconventional * mahajan@phy.iitb.ac.in nature of its elementary excitations, which result from a chargeless sector of spin-1/2 fermions (commonly known as spinons), also drew interest from theorists and experimentalists [1,20,21].…”

mentioning

confidence: 99%

Sc2Ga2CuO7: A possible quantum spin liquid near the percolation threshold

et al. 2015

View full text Add to dashboard Cite

Sc 2 Ga 2 CuO 7 (SGCO) crystallizes in a hexagonal structure (space group: P 6 3 /mmc), which can be seen as an alternating stacking of single and double triangular layers. Combining neutron, x-ray, and resonant x-ray diffraction, we establish that the single triangular layers are mainly populated by nonmagnetic Ga 3+ ions (85% Ga and 15% Cu), while the bilayers have comparable population of Cu 2+ and Ga 3+ ions (43% Cu and 57% Ga). Our susceptibility measurements in the temperature range 1.8-400 K give no indication of any spin-freezing or magnetic long-range order (LRO). We infer an effective paramagnetic moment μ eff = 1.79 ± 0.09 μ B and a Curie-Weiss temperature θ CW of about −44 K, suggesting antiferromagnetic interactions between the Cu 2+ (S = 1/2) ions. Low-temperature neutron powder diffraction data showed no evidence for LRO down to 1.5 K. In our specific heat data as well, no anomalies were found down to 0.35 K, in the field range 0-140 kOe. The magnetic specific heat C m , exhibits a broad maximum at around 2.5 K followed by a nearly power law C m ∝ T α behavior at lower temperatures, with α increasing from 0.3 to 1.9 as a function of field for fields up to 90 kOe and then remaining at 1.9 for fields up to 140 kOe. Our results point to a disordered ground state in SGCO.

show abstract

Quantum Spin Liquid Emerging from Antiferromagnetic Order by Introducing Disorder

Cited by 76 publications

References 33 publications

Spin liquid state in the disordered triangular latticeSc2Ga2CuO7revealed by NMR

Spin liquid state in the disordered triangular latticeSc2Ga2CuO7revealed by NMR

Effects of strong disorder in strongly correlated superconductors

Sc2Ga2CuO7: A possible quantum spin liquid near the percolation threshold

Contact Info

Product

Resources

About