P. W. Anderson

1987, Science - Article

The oxide superconductors, particularly those recently discovered that are based on La(2)CuO(4), have a set of peculiarities that suggest a common, unique mechanism: they tend in every case to occur n...more

Unconventional superconductivity in magic-angle graphene superlattices

Yuan Cao, Valla Fatemi, Shiang Fang, Kenji Watanabe, Takashi Taniguchi, Efthimios Kaxiras, Pablo Jarillo-Herrero

2018, Nature - Article

The behaviour of strongly correlated materials, and in particular unconventional superconductors, has been studied extensively for decades, but is still not well understood. This lack of theoretical u...more

Spin Liquid State in an Organic Mott Insulator with a Triangular Lattice

Y. Shimizu, K. Miyagawa, K. Kanoda, M. Maesato, G. Saito

2003, Physical Review Letters - Article

1H NMR and static susceptibility measurements have been performed in an organic Mott insulator with a nearly isotropic triangular lattice, kappa-(BEDT-TTF)2Cu2(CN)(3), which is a model system of frust...more

Quantum spin liquids: a review

Lucile Savary, Leon Balents

2016, Reports on Progress in Physics - Article

Quantum spin liquids may be considered 'quantum disordered' ground states of spin systems, in which zero-point fluctuations are so strong that they prevent conventional magnetic long-range o...more

Fractionalized excitations in the spin-liquid state of a kagome-lattice antiferromagnet

Tian-Heng Han, Joel S. Helton, Shaoyan Chu, Daniel G. Nocera, Jose A. Rodriguez-Rivera, Collin Broholm, Young S. Lee

2012, Nature - Article

Neutron scattering measurements on single-crystal samples of the mineral herbertsmithite, which is a spin-1/2 kagome-lattice antiferromagnet, provide evidence of fractionalized spin excitations at low...more

Proximate Kitaev quantum spin liquid behaviour in a honeycomb magnet

A. Banerjee, C. A. Bridges, J.-Q. Yan, A. A. Aczel, L. Li, M. B. Stone, G. E. Granroth, M. D. Lumsden, Y. Yiu, J. Knolle, S. Bhattacharjee, D. L. Kovrizhin, R. Moessner, D. A. Tennant, D. G. Mandrus, S. E. Nagler

2016, Nature Materials - Article

Quantum spin liquids (QSLs) are topological states of matter exhibiting remarkable properties such as the capacity to protect quantum information from decoherence. Whereas their featureless ground sta...more

Quantum spin liquid states

Yi Zhou, Kazushi Kanoda, Tai-Kai Ng

2017, Reviews of Modern Physics - Article

This is an introductory review of the physics of quantum spin liquid states. Quantum magnetism is a rapidly evolving field, and recent developments reveal that the ground states and low-energy physics...more

Quantum spin liquid emerging in two-dimensional correlated Dirac fermions

Z. Y. Meng, T. C. Lang, S. Wessel, F. F. Assaad, A. Muramatsu

2010, Nature - Article

At sufficiently low temperatures, condensed-matter systems tend to develop order. A notable exception to this behaviour is the case of quantum spin liquids, in which quantum fluctuations prevent a tra...more

Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid

Y. Kasahara, T. Ohnishi, Y. Mizukami, O. Tanaka, Sixiao Ma, K. Sugii, N. Kurita, H. Tanaka, J. Nasu, Y. Motome, T. Shibauchi, Y. Matsuda

2018, Nature - Article

The quantum Hall effect in two-dimensional electron gases involves the flow of topologically protected dissipationless charge currents along the edges of a sample. Integer or fractional electrical con...more

Neutron scattering in the proximate quantum spin liquid α-RuCl3

Arnab Banerjee, Jiaqiang Yan, Johannes Knolle, Craig A Bridges, Matthew B Stone, Mark D Lumsden, David G Mandrus, David A Tennant, Roderich Moessner, Stephen E Nagler

2017, Science - Article

The Kitaev quantum spin liquid (KQSL) is an exotic emergent state of matter exhibiting Majorana fermion and gauge flux excitations. The magnetic insulator α-RuCl3 is thought to realize a pr...more

Quantum Excitations in Quantum Spin Ice

Kate A. Ross, Lucile Savary, Bruce D. Gaulin, Leon Balents

2011, Physical Review X - Article

Recent work has highlighted remarkable effects of classical thermal fluctuations in the dipolar spin ice compounds, such as “artificial magnetostatics,” manifesting as Coulombic power-law spin correla...more

An End to the Drought of Quantum Spin Liquids

Patrick A Lee

2008, Science - Article

Pyrochlore Antiferromagnet: A Three-Dimensional Quantum Spin Liquid

B. Canals, C. Lacroix

1998, Physical Review Letters - Article

The quantum pyrochlore antiferromagnet is studied by perturbative expansions and exact diagonalization of small clusters. We find that the ground state is a spin-liquid state: The spin-spin correlatio...more

Experimental Realization of a 2D Fractional Quantum Spin Liquid

R. Coldea, D. A. Tennant, A. M. Tsvelik, Z. Tylczynski

2001, Physical Review Letters - Article

The ground-state ordering and dynamics of the two-dimensional S = 1/2 frustrated Heisenberg antiferromagnet Cs(2)CuCl(4) are explored using neutron scattering in high magnetic fields. We find that the...more

Highly Mobile Gapless Excitations in a Two-Dimensional Candidate Quantum Spin Liquid

Minoru Yamashita, Norihito Nakata, Yoshinori Senshu, Masaki Nagata, Hiroshi M. Yamamoto, Reizo Kato, Takasada Shibauchi, Yuji Matsuda

2010, Science - Article

The nature of quantum spin liquids, a novel state of matter where strong quantum fluctuations destroy the long-range magnetic order even at zero temperature, is a long-standing issue in physics. We me...more

Emergence and Frustration of Magnetism with Variable-Range Interactions in a Quantum Simulator

R. Islam, C. Senko, W. C. Campbell, S. Korenblit, J. Smith, A. Lee, E. E. Edwards, C.-C. J. Wang, J. K. Freericks, C. Monroe

2013, Science - Article

Frustration, or the competition between interacting components of a network, is often responsible for the emergent complexity of many-body systems. For instance, frustrated magnetism is a hallmark of ...more

Quantum spin liquid in the spin-1∕2 triangular antiferromagnet EtMe3Sb[Pd(dmit)2]2

T. Itou, A. Oyamada, S. Maegawa, M. Tamura, R. Kato

2008, Physical Review B - Article

The family of layered organic salts X[Pd(dmit)2]2 are Mott insulators and form scalene-triangular spin-1∕2 systems. Among them, EtMe3Sb[Pd(dmit)2]2 has a nearly regular-triangular lattice. We have inv...more

Quantum spin ice: a search for gapless quantum spin liquids in pyrochlore magnets

M J P Gingras, P A McClarty

2014, Reports on Progress in Physics - Article

The spin ice materials, including Ho2Ti2O7 and Dy2Ti2O7, are rare-earth pyrochlore magnets which, at low temperatures, enter a constrained paramagnetic state with an emergent gauge freedom. Spin ices ...more

Scattering Continuum and Possible Fractionalized Excitations in α-RuCl3

Luke J Sandilands, Yao Tian, Kemp W Plumb, Young-June Kim, Kenneth S Burch

2015, Physical Review Letters - Article

The combination of electronic correlation and spin-orbit coupling is thought to precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid state...more

Thermal-transport measurements in a quantum spin-liquid state of the frustrated triangular magnet κ-(BEDT-TTF)2Cu2(CN)3

Minoru Yamashita, Norihito Nakata, Yuichi Kasahara, Takahiko Sasaki, Naoki Yoneyama, Norio Kobayashi, Satoshi Fujimoto, Takasada Shibauchi, Yuji Matsuda

2008, Nature Physics - Article

Low-temperature thermal-transport measurements of a frustrated organic magnet in which a quantum spin-liquid is believed to exist, suggest that the emergence of this state is accompanied by a spin-gap...more

Colloquium: Herbertsmithite and the search for the quantum spin liquid

M. R. Norman

2016, Reviews of Modern Physics - Article

Quantum spin liquids form a novel class of matter where, despite the existence of strong exchange interactions, spins do not order down to the lowest measured temperature. Typically, these occur in la...more

Spin liquid ground state of the spin-12 square J1-J2 Heisenberg model

Hong-Chen Jiang, Hong Yao, Leon Balents

2012, Physical Review B - Article

We perform highly accurate density matrix renormalization group (DMRG) simulations to investigate the ground-state properties of the spin-1/2 antiferromagnetic square lattice Heisenberg J1-J2 model. B...more

Concept and realization of Kitaev quantum spin liquids

Hidenori Takagi, Tomohiro Takayama, George Jackeli, Giniyat Khaliullin, Stephen E. Nagler

2019, Nature Reviews Physics - Article

The Kitaev model is an exactly solvable S = 1/2 spin model on a 2D honeycomb lattice, in which the spins fractionalize into Majorana fermions and form a topological quantum spin liquid (QSL) in the gr...more

Evidence for a gapped spin-liquid ground state in a kagome Heisenberg antiferromagnet

Mingxuan Fu, Takashi Imai, Tian-Heng Han, Young S Lee

2015, Science - Article

The kagome Heisenberg antiferromagnet is a leading candidate in the search for a spin system with a quantum spin-liquid ground state. The nature of its ground state remains a matter of active debate. ...more

Physics of projected wavefunctions

Claudius Gros

1989, Annals of Physics - Article

We present and discuss a variational approach to the one band Hubbard model in the limit of a large on-site Coulomb repulsion. The trial wavefunctions are the projected wavefunctions, generalized Gutz...more

Coulombic Quantum Liquids in Spin-1/2 Pyrochlores

Lucile Savary, Leon Balents

2012, Physical Review Letters - Article

We develop a nonperturbative gauge mean field theory (gMFT) method to study a general effective spin-1/2 model for magnetism in rare earth pyrochlores. gMFT is based on a novel exact slave-particle fo...more

Dynamics of a Two-Dimensional Quantum Spin Liquid: Signatures of Emergent Majorana Fermions and Fluxes

J. Knolle, D. L. Kovrizhin, J. T. Chalker, R. Moessner

2014, Physical Review Letters - Article

We provide a complete and exact theoretical study of the dynamical structure factor of a two-dimensional quantum spin liquid in gapless and gapped phases, as realized in Kitaev’s honeycomb model. We s...more

Evidence for a Field-Induced Quantum Spin Liquid in α-RuCl3

S-H Baek, S-H Do, K-Y Choi, Y S Kwon, A U B Wolter, S Nishimoto, Jeroen van den Brink, B Büchner

2017, Physical Review Letters - Article

We report a ^{35}Cl nuclear magnetic resonance study in the honeycomb lattice α-RuCl_{3}, a material that has been suggested to potentially realize a Kitaev quantum spin liquid (QSL) ground state. Our...more

Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4

Joseph A. M. Paddison, Marcus Daum, Zhiling Dun, Georg Ehlers, Yaohua Liu, Matthew B. Stone, Haidong Zhou, Martin Mourigal

2016, Nature Physics - Article

A detailed and systematic neutron-scattering study uncovers a continuum of magnetic excitations down to 0.06 K in the triangular quantum magnet YbMgGaO4 — an observation consistent with quantum spin l...more

Quantum spin liquids

C Broholm, R J Cava, S A Kivelson, D G Nocera, M R Norman, T Senthil

2020, Science - Article

Spin liquids are quantum phases of matter with a variety of unusual features arising from their topological character, including "fractionalization"-elementary excitations that behave as fra...more

Jordan-Wigner transformation for quantum-spin systems in two dimensions and fractional statistics

Eduardo Fradkin

1989, Physical Review Letters - Article

I construct a Jordan-Wigner transformation for spin-one-half quantum systems on two-dimensional lattices. I show that the spin-one-half XY (i.e., a hard-core Bose system) is equivalent (on any two-dim...more

Correlation Effects in Quantum Spin-Hall Insulators: A Quantum Monte Carlo Study

M. Hohenadler, T. C. Lang, F. F. Assaad

2011, Physical Review Letters - Article

We consider the Kane-Mele model supplemented by a Hubbard U term. The phase diagram is mapped out using projective auxiliary field quantum Monte Carlo simulations. The quantum spin liquid of the Hubba...more

Controlled expansion for certain non-Fermi-liquid metals

David F. Mross, John McGreevy, Hong Liu, T. Senthil

2010, Physical Review B - Article

The destruction of Fermi-liquid behavior when a gapless Fermi surface is coupled to a fluctuating gapless boson field is studied theoretically. This problem arises in a number of different contexts in...moreEvidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate

Yao Shen, Yao-Dong Li, Hongliang Wo, Yuesheng Li, Shoudong Shen, Bingying Pan, Qisi Wang, H. C. Walker, P. Steffens, M. Boehm, Yiqing Hao, D. L. Quintero-Castro, L. W. Harriger, M. D. Frontzek, Lijie Hao, Siqin Meng, Qingming Zhang, Gang Chen, Jun Zhao

2016, Nature - Article

A spin excitation continuum across a large region of the Brillouin zone that persists at near-zero temperatures provides evidence for a quantum spin liquid state with a spinon Fermi surface in YbMgGaO...more

Physics of the Kitaev Model: Fractionalization, Dynamical Correlations, and Material Connections

M. Hermanns, I. Kimchi, J. Knolle

2017, Annual Review of Condensed Matter Physics - Article

Quantum spin liquids have fascinated condensed matter physicists for decades because of their unusual properties such as spin fractionalization and long-range entanglement. Unlike conventional symmet...more

Rare-Earth Triangular Lattice Spin Liquid: A Single-Crystal Study of YbMgGaO4

Yuesheng Li, Gang Chen, Wei Tong, Li Pi, Juanjuan Liu, Zhaorong Yang, Xiaoqun Wang, Qingming Zhang

2015, Physical Review Letters - Article

YbMgGaO4, a structurally perfect two-dimensional triangular lattice with an odd number of electrons per unit cell and spin-orbit entangled effective spin-1/2 local moments for the Yb(3+) ions, is like...more

Excitations in the field-induced quantum spin liquid state of α-RuCl3

Arnab Banerjee, Paula Lampen-Kelley, Johannes Knolle, Christian Balz, Adam Anthony Aczel, Barry Winn, Yaohua Liu, Daniel Pajerowski, Jiaqiang Yan, Craig A. Bridges, Andrei T. Savici, Bryan C. Chakoumakos, Mark D. Lumsden, David Alan Tennant, Roderich Moessner, David G. Mandrus, Stephen E. Nagler

2018, npj Quantum Materials - Article

The celebrated Kitaev quantum spin liquid (QSL) is the paradigmatic example of a topological magnet with emergent excitations in the form of Majorana Fermions and gauge fluxes. Upon breaking of time-r...more

Kapellasite: A Kagome Quantum Spin Liquid with Competing Interactions

B. Fåk, E. Kermarrec, L. Messio, B. Bernu, C. Lhuillier, F. Bert, P. Mendels, B. Koteswararao, F. Bouquet, J. Ollivier, A. D. Hillier, A. Amato, R. H. Colman, A. S. Wills

2012, Physical Review Letters - Article

Magnetic susceptibility, NMR, muon spin relaxation, and inelastic neutron scattering measurements show that kapellasite, Cu3Zn(OH)6Cl2, a geometrically frustrated spin-1/2 kagome antiferromagnet polym...more

Ultracold quantum gases and lattice systems: quantum simulation of lattice gauge theories

U.‐J. Wiese

2013, Annalen der Physik - Article

Abelian and non‐Abelian gauge theories are of central importance in many areas of physics. In condensed matter physics, Abelian U(1) lattice gauge theories arise in the description of certain quantum ...more

Field- and pressure-induced magnetic quantum phase transitions in TlCuCl3

Masashige Matsumoto, B. Normand, T. M. Rice, Manfred Sigrist

2004, Physical Review B - Article

Thallium copper chloride is a quantum spin liquid of S=1/2 Cu2+ dimers. Interdimer superexchange interactions give a three-dimensional magnon dispersion and a spin gap significantly smaller than the d...moreCompass models: Theory and physical motivations

Zohar Nussinov, Jeroen van den Brink

2015, Reviews of Modern Physics - Article

Compass models are theories of matter in which the couplings between the internal spin (or other relevant field) components are inherently spatially (typically, direction) dependent. A simple illustra...more

Atomic Quantum Gases in Kagomé Lattices

L. Santos, M. A. Baranov, J. I. Cirac, H.-U. Everts, H. Fehrmann, M. Lewenstein

2004, Physical Review Letters - Article

We demonstrate the possibility of creating and controlling an ideal and trimerized optical Kagomé lattice, and study the low temperature physics of various atomic gases in such lattices. In the trimer...more

B. Keimer, J. E. Moore

2017, Nature Physics - Article

The physical description of all materials is rooted in quantum mechanics, which describes how atoms bond and electrons interact at a fundamental level. Although these quantum effects can in many cases...more

From high temperature superconductivity to quantum spin liquid: progress in strong correlation physics

Patrick A Lee

2007, Reports on Progress in Physics - Article

This review gives a rather general discussion of high temperature superconductors as an example of a strongly correlated material. The argument is made that in view of the many examples of unconventio...more

Gapless spin liquid of an organic triangular compound evidenced by thermodynamic measurements

Satoshi Yamashita, Takashi Yamamoto, Yasuhiro Nakazawa, Masafumi Tamura, Reizo Kato

2011, Nature Communications - Article

In frustrated magnetic systems, long-range ordering is forbidden and degeneracy of energy states persists, even at extremely low temperatures. Under certain conditions, these systems form an exotic qu...more

Fermionic response from fractionalization in an insulating two-dimensional magnet

J. Nasu, J. Knolle, D. L. Kovrizhin, Y. Motome, R. Moessner

2016, Nature Physics - Article

An intriguing state of matter known as a quantum spin liquid has been predicted to host Majorana fermions. A detailed theoretical and numerical analysis re-interprets existing Raman data for α-RuCl3 a...more

Quantum-spin-liquid states in the two-dimensional kagome antiferromagnets ZnxCu4−x(OD)6Cl2

S.-H. Lee, H. Kikuchi, Y. Qiu, B. Lake, Q. Huang, K. Habicht, K. Kiefer

2007, Nature Materials - Article

A three-dimensional system of interacting spins typically develops static long-range order when it is cooled. If the spins are quantum (S=1/2), however, novel quantum paramagnetic states may appear. T...more

Ravi Yadav, Nikolay A. Bogdanov, Vamshi M. Katukuri, Satoshi Nishimoto, Jeroen van den Brink, Liviu Hozoi

2016, Scientific Reports - Article

Large anisotropic exchange in 5d and 4d oxides and halides open the door to new types of magnetic ground states and excitations, inconceivable a decade ago. A prominent case is the Kitaev spin liquid,...more

First-Principles Study of the Honeycomb-Lattice Iridates Na2IrO3 in the Presence of Strong Spin-Orbit Interaction and Electron Correlations

Youhei Yamaji, Yusuke Nomura, Moyuru Kurita, Ryotaro Arita, Masatoshi Imada

2014, Physical Review Letters - Article

An effective low-energy Hamiltonian of itinerant electrons for iridium oxide Na2IrO3 is derived by an ab initio downfolding scheme. The model is then reduced to an effective spin model on a honeycomb ...more

Gapless quantum spin liquid ground state in the two-dimensional spin-1/2 triangular antiferromagnet YbMgGaO4

Yuesheng Li, Haijun Liao, Zhen Zhang, Shiyan Li, Feng Jin, Langsheng Ling, Lei Zhang, Youming Zou, Li Pi, Zhaorong Yang, Junfeng Wang, Zhonghua Wu, Qingming Zhang

2015, Scientific Reports - Article

Quantum spin liquid (QSL) is a novel state of matter which refuses the conventional spin freezing even at 0 K. Experimentally searching for the structurally perfect candidates is a big challenge in co...more

Superconductivity in a Copper(II)‐Based Coordination Polymer with Perfect Kagome Structure

Xing Huang, Shuai Zhang, Liyao Liu, Lei Yu, Genfu Chen, Wei Xu, Daoben Zhu

2017, Angewandte Chemie International Edition - Article

A highly crystalline copper(II) benzenehexathiolate coordination polymer (Cu-BHT) has been prepared. The two-dimensional kagome structure has been confirmed by powder X-ray diffraction, high-resolutio...more

Exotic phases induced by strong spin-orbit coupling in ordered double perovskites

Gang Chen, Rodrigo Pereira, Leon Balents

2010, Physical Review B - Article

We construct and analyze a microscopic model for insulating rocksalt ordered double perovskites, with the chemical formula A2BB′O6, where the B′ atom has a 4d1 or 5d1 electronic configuration and form...moreSeeing the light: Experimental signatures of emergent electromagnetism in a quantum spin ice

Owen Benton, Olga Sikora, Nic Shannon

2012, Physical Review B - Article

The “spin-ice” state found in the rare-earth pyrochlore magnets Ho2Ti2O7 and Dy2Ti2O7 offers a beautiful realization of classical magnetostatics, complete with magnetic monopole excitations. It has be...more

Generic quantum spin ice

SungBin Lee, Shigeki Onoda, Leon Balents

2012, Physical Review B - Article

We consider possible exotic ground states of quantum spin ice as realized in rare earth pyrochlores. Prior work [Savary and Balents, Phys. Rev. Lett. 108, 037202 (2012).PRLTAO0031-900710.1103/PhysRevL...more

Instability of a quantum spin liquid in an organic triangular-lattice antiferromagnet

T. Itou, A. Oyamada, S. Maegawa, R. Kato

2010, Nature Physics - Article

Experimental data suggest that EtMe3Sb[Pd(dmit)2]2, an organic system with a two-dimensional triangular lattice, undergoes a low-temperature phase transition that is not accompanied by classical antif...moreGapless Spin Excitations in the Field-Induced Quantum Spin Liquid Phase of α-RuCl3

Jiacheng Zheng, Kejing Ran, Tianrun Li, Jinghui Wang, Pengshuai Wang, Bin Liu, Zheng-Xin Liu, B Normand, Jinsheng Wen, Weiqiang Yu

2017, Physical Review Letters - Article

α-RuCl_{3} is a leading candidate material for the observation of physics related to the Kitaev quantum spin liquid (QSL). By combined susceptibility, specific-heat, and nuclear-magnetic-resonance mea...more

Magnetic and non-magnetic phases of a quantum spin liquid

F. L. Pratt, P. J. Baker, S. J. Blundell, T. Lancaster, S. Ohira-Kawamura, C. Baines, Y. Shimizu, K. Kanoda, I. Watanabe, G. Saito

2011, Nature - Article

Characterization of a quantum spin liquidTheoretical predictions of the existence of an exotic state of matter called a quantum spin liquid have been supported by experimental evidence, but many funda...more