4 Corners Southwest Ontario Condensed Matter Physics Symposium 2016

COVID-19 information for PI Residents and Visitors

Conference Date: 
Thursday, May 12, 2016 (All day)
Scientific Areas: 
Quantum Matter

 

This ninth annual one-day symposium aims to provide an opportunity for condensed matter researchers in Southwest Ontario to gather and discuss informally their most recent research.  The general format of the meeting consists of 2 guest speakers and 5-7 contributed talks.  The names of the contributing speakers and title of their talks will be announced later.  Registration begins at 9:30 am.  The meeting is expected to start around 9:45 am and end between 5-5:30 pm.  A lunch will be provide by the Black Hole Bistro.

There will be two keynote speakers for the symposium;  Professor Kazushi Kanoda from the University of Tokyo and Professor Roderich Moessner from the Max Planck Institute for the Physics of Complex Systems.  Professor Kanoda's talk is entitled "Organic materials: all-in-one systems for Mott Physics - Quantum criticality, preformed pairs and spin liquids" while Professor Moesnner's talk is titled "Random disorder in spin liquids".

Past speakers for this event were as follows:
 
 
The registration fee for this event is $10.00 CAD, which includes lunch and a coffee break.
 
Registration for the symposium is now closed.
 
 

Keynote Speakers:

  • Kazushi Kanoda, University of Tokyo
  • Roderich MoessnerMax Planck Institute for the Physics of Complex Systems

Speakers:

  • Raffi Budakian, University of Waterloo
  • Alannah Hallas, McMaster University
  • Takashi Imai, McMaster University
  • Young-June Kim, University of Toronto
  • Jeff Rau, University of Waterloo
  • Adam Tsen, University of Waterloo
  • Yuan Wan, Perimeter Institute
  • Rabaya Bagum, McMaster University
  • Peter Barfuss, University of Illinois Urbana-Champaign
  • Alina Barnett, McMaster University
  • Grigory Bednik, University of Waterloo
  • Anton Borissov, University of Waterloo
  • Raffi Budakian, University of Waterloo
  • Connor Buhariwalla, McMaster University
  • Yipeng Cai, McMaster University
  • Juan Carrasquilla, Perimeter Institute
  • Li Ern Chern, University of Toronto
  • Mirela Dragomir, McMaster University
  • Bruce Gaulin, McMaster University
  • Nuwansiri Nirosh Getangama, University of Western Ontario
  • Michel Gingras, University of Waterloo
  • Alannah Hallas, McMaster University
  • David Hawthorne, University of Waterloo
  • Reid Hayes, University of Waterloo
  • Lauren Hayward-Sierens, Perimeter Institute & Univeristy of Waterloo
  • Chris Herdman, Institute for Quantum Computing
  • Ciaran Hickey, University of Toronto
  • Robert Hill, University of Waterloo
  • Wen Huang, McMaster University
  • Yejin Huh, University of Toronto
  • Emy Illes, University of Guelph
  • Takashi Imai, McMaster University
  • Heung-Sik Kim, University of Toronto
  • Young-June Kim, University of Toronto
  • Jan Kycia, University of Waterloo
  • Etienne Lantagne-Hurtubise, Perimeter Institute
  • Yang Liu, University of Western Ontario
  • Kazushi Kanoda, University of Toyko
  • Bohdan Kulchytskyy, University of Waterloo
  • Sung-Sik Lee, Perimeter Institute & McMaster University
  • Graeme Luke, McMaster University
  • Kyle Qianli Ma, McMaster University
  • Dalini Majaraj, McMaster University
  • John Malcolm, University of Guelph
  • Christopher McMahon, University of Waterloo
  • Ashley Milsted, Perimeter Institute
  • Roderich MoessnerMax Planck Institute for the Physics of Complex Systems
  • Matthew Nugent, McMaster University
  • Adarsh Patri, University of Waterloo
  • David Pomaranski, University of Waterloo
  • Jeff Rau, University of Waterloo
  • Jennifer Reid, University of Waterloo
  • Julian Rincon, Perimeter Institute
  • Gabriele Sala, McMaster University
  • Robert Schaffer, University of Toronto
  • Jianing Sheng, University of Waterloo
  • Erik Sorensen, McMaster University
  • Sopheak Sorn, Perimeter Institute
  • Sean Takahashi, McMaster University
  • William Toews, University of Waterloo
  • Giacomo Torlai, Univeristy of Waterloo
  • Adam Tsen, University of Waterloo
  • Yuan Wan, Perimeter Institute
  • Chenjie Wang, Perimeter Institute
  • Murray Wilson, McMaster University
  • Rachel Wortis, Trent University
  • Shuo Yang, Perimeter Institute

Time

Event

Location

09:00 – 09:55

Registration and Coffee

Atrium

09:55 – 10:00

Welcome Address 
Michel Gingras, University of Waterloo

Lazaridis Theatre

 

Morning Session
 Chair: Michel Gingras, University of Waterloo

Lazaridis Theatre

10:00 – 11:00

Roderich Moessner,
Max Planck Institute for the Physics of Complex Systems
Disorder in Frustrated Magnets

Lazaridis Theatre

11:00 – 11:30

Adam Tsen, University of Waterloo
Superconductivity and Charge Density Waves in the Clean 2D Limit

Lazaridis Theatre

11:30 – 12:00

Young-June Kim, University of Toronto
Honeycomb lattice quantum magnets with strong spin-orbit coupling

Lazaridis Theatre

12:00 – 1:30

Lunch Break

2nd floor bistro

 

 

Afternoon Session #1
Chair: Jeff Rau, University of Waterloo

Lazaridis Theatre

1:30 – 2:30

Kazushi Kanoda, University of Tokyo
Organic Materials:
All-in-One Systems for Mott Physics, Quantum Criticality,
Preformed Pairs and Spin Liquids

Lazaridis Theatre

2:30 – 3:00

Takashi Imai, McMaster University
Evidence for a Gapped Spin Liquid Ground State in
Herbertsmithite Kagome Heisenberg Antiferromagnet

Lazaridis Theatre

3:00 – 3:30

Raffi Budakian, University of Waterloo
Stochastic Resonance Magnetic Force Microscopy:
A Technique for Nanoscale Imaging of Vortex Dynamics

Lazaridis Theatre

3:30 – 3:40

Conference Photo

Atrium

3:40 – 4:00

Afternoon Coffee Break

1st floor bistro

 

Afternoon Session #2
Chair: David Hawthorn, University of Waterloo

Lazaridis Theatre

4:00 – 4:30

Jeff Rau, University of Waterloo
Spin Slush in an Extended Spin Ice Model

 

Lazaridis Theatre

4:30 – 5:00

Alannah Hallas, McMaster University
Universal Dynamic Magnetism in the Ytterbium Pyrochlores

Lazaridis Theatre

5:00 – 5:30

Yuan Wan, Perimeter Institute
Spinon Walk in Quantum Spin Ice

Lazaridis Theatre

5:30 – 5:35

Closing Address
Michel Gingras, University of Waterloo

Lazaridis Theatre

 

Keynote Talks

Kazushi Kanoda, University of Tokyo

Organic materials: all-in-one systems for Mott physics - Quantum criticality, preformed pairs and spin liquids

A many-body quantum system on the verge of instability between competing ground states exhibits emergent phenomena. Interacting electrons on triangular lattices are likely subjected to multiple instabilities in the charge and spin degrees of freedom, affording diverse phenomena related to the Mott physics. The molecular conductors are superior model systems for studying the Mott physics because of the designability and controllability of material parameters such as lattice geometry and bandwidth by chemical substitution and/or pressure. In this symposium, I first introduce the fundamentals of organic materials and then present various quantum manifestations that interacting electrons in triangular-lattice organics show under variable correlation on the verge of the Mott metal-insulator transition. The topics include i) the quantum criticality of the Mott transition revealed by the resistivity that obeys quantum-critical scaling, ii) the pseudo-gap-like behavior of the metallic state, which is found to originate from preformed Cooper pairs that persist up to twice as high as Tc, and iii) the spin liquid state that emerges in the Mott insulating state, depending on the lattice geometry. I may touch the recent finding on a doped triangular lattice that exhibits a possible BEC-to-BCS crossover in superconductivity.

The work presented here was performed in collaboration with T. Furukawa, H. Oike, J. Ibuka, M. Urai, Y. Suzuki, K. Miyagawa (UTokyo), Y. Shimizu (Nagoya Univ.), M. Ito, H. Taniguchi (Saitama Univ.) and R. Kato (RIKEN)

Roderich Moessner, Max Planck Institute for the Physics of Complex Systems

Disorder in spin liquids

Beyond their deceptively featureless ground states, spin liquids are particularly remarkable in the exotic nature of their (fractionalised and gauge charged) excitations. Quenched disorder can be instrumental in nucleating or localising defects with unusual properties, revealing otherwise hidden features of these topological many-body states. This talk discusses how to turn the nuisance of disorder into a powerful probe and origin of new collective behaviour. 

Contributed Talks

Raffi Budakian, University of Waterloo

Stochastic Resonance Magnetic Force Microscopy: A Technique for Nanoscale Imaging of Vortex Dynamics

In this talk, I will describe a new technique—stochastic resonance magnetic force microscopy (SRMFM)—developed in my group for imaging the vortex dynamics in multiply connected superconducting devices. Unlike existing techniques, which directly image vortices, our technique relies on the mechanism of stochastic resonance to image the fluctuations between different vortex configurations. 

I will present data, taken using Josephson junction arrays and ring structures, that reveal striking geometric patterns which emerge when the energy of different vortex configurations become degenerate at well-defined positions of a magnetic tip that is scanned above the surface of the device. By analyzing the fluctuation rate as a function of temperature or external field, we obtain detailed information regarding the energy barriers connecting different vortex configurations, as well as energy scales associated with vortex-vortex interactions. The technique also provides a convenient means to manipulate vortices in multiply connected superconducting structures, which may prove useful in certain topological quantum-computing applications.

Alannah Hallas, McMaster University

Universal Dynamic Magnetism in the Ytterbium Pyrochlores

The ytterbium pyrochlores, Yb2B2O7, are a family of materials with a remarkable diversity in their low-temperature physics. At the heart of their interesting physics is the proximity of their ground states to numerous competing phases. These proximate phases make the Yb pyrochlores very sensitive to perturbations such as pressure and off-stoichiometry. I will present a study of the effects of chemical pressure on the ytterbium pyrochlores, in which substitution of a non-magnetic constituent alters the lattice size and consequently inflicts an internal pressure on the system. We find that although each of Yb2B2O7 (B = Ge, Ti, Sn) exhibits a distinct dipole ordered state, there is a ubiquitous nature to their spin excitations. Furthermore, these spin excitations are highly unconventional in their own right and may hint at a hidden order parameter.

Takashi Imai, McMaster University

Evidence for a Gapped Spin Liquid Ground State in Herbertsmithite Kagome Heisenberg Antiferromagnet

The kagome lattice in a mineral compound "Herbertsmithite" represents structurally the most ideal kagome Heisenberg antiferromagnet known to date.  Herbertsmithite does not undergo a magnetic long-range order or spin freezing at least down to ~J/2000.  We will present 17-Oxygen and 2-Deuterium single crystal NMR study of Herbertsmithite.   We will demonstrate that the ground state of the kagome plane has a spin gap ~ 0.05J [1], and ~5% excess Cu2+ ions occupying the out-of-plane Zn2+ sites are the only defects [2].

[1] M. Fu et al., Science 350, 655 (2015).

[2] T. Imai et al., Phys. Rev. B 84, 020411 (2011). 

Young-June Kim, University of Toronto

Honeycomb lattice quantum magnets with strong spin-orbit coupling

In recent years, there has been much interest in honeycomb lattice quantum magnets described by Kitaev-Heisenberg Hamiltonian. For example, honeycomb lattice iridates, such as Na2IrO3 and Li2IrO3 have been intensely scrutinized. Recently, we proposed that a 4d honeycomb magnet α-RuCl3 is a promising candidate material in which Kitaev physics could be studied. I will give an overview of the physics of alpha-RuCl3, and talk about recent experimental and theoretical advances.

Jeff Rau, University of Waterloo

Spin Slush in an Extended Spin Ice Model

We introduce a new classical spin liquid on the pyrochlore lattice by extending spin ice with further neighbour interactions.  This disorder-free spin model exhibits a form of dynamical heterogeneity with extremely slow relaxation for some spins while others fluctuate quickly down to zero temperature. We thus call this state "spin slush", in analogy to the heterogeneous mixture of solid and liquid water. This behaviour is driven by the structure of the ground state manifold that extends the two-in/two-out ice states to include branching structures built from three-in/one-out, three-out/one-in and all-in/all-out defects. Distinctive liquid-like patterns in the spin correlations serve as a signature of this intermediate range order. Finally, we discuss possible applications to materials as well the effects of quantum tunneling.

Adam Tsen, University of Waterloo

Superconductivity and Charge Density Waves in the Clean 2D Limit

We have recently demonstrated an experimental platform to isolate 2D materials that are unstable in the ambient environment. I will discuss our recent studies of the charge density wave compound 1T-TaS2 and superconducting 2H-NbSe¬ in the atomically thin limit, made possible using this technique. In TaS2, we uncover a new surface charge density wave transition that is distinct from that in the bulk layers, as well as demonstrate continuous electrical control over this phase transition. In NbSe2, a small perpendicular magnetic field induces a transition to a quantum metallic phase, the resistivity of which obeys a unique field-scaling consistent with that predicted for a Bose metal. These methods and experiments open new doors for the study of other correlated 2D systems in the immediate future.

Yuan Wan, Perimeter Institute

Spinon Walk in Quantum Spin Ice

Quantum spin ice is a frustrated magnet that displays rich emergent phenomena. For example, the magnetic moments carried by the spins may separate into mobile magnetic charges, producing quantum fractional excitations known as spinons. The spinon moves in a background of disordered spins, and its motion is strongly coupled to the spin background. In this talk, I will demonstrate that the spinon dynamics can be described as a quantum walk with entropy-induced memory.  Our numerical simulation shows that the dynamics of spinon exhibits a remarkable renormalization phenomenon: the spinon behaves as a massive free particle at low energy despite its strong coupling at the lattice scale.

 

 

 

Thursday May 12, 2016
Speaker(s): 

Quantum spin ice is a frustrated magnet that displays rich emergent phenomena. For example, the magnetic moments carried by the spins may separate into mobile magnetic charges, producing quantum fractional excitations known as spinons. The spinon moves in a background of disordered spins, and its motion is strongly coupled to the spin background. In this talk, I will demonstrate that the spinon dynamics can be described as a quantum walk with entropy-induced memory.

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

The ytterbium pyrochlores, Yb2B2O7, are a family of materials with a remarkable diversity in their low-temperature physics. At the heart of their interesting physics is the proximity of their ground states to numerous competing phases. These proximate phases make the Yb pyrochlores very sensitive to perturbations such as pressure and off-stoichiometry. I will present a study of the effects of chemical pressure on the ytterbium pyrochlores, in which substitution of a non-magnetic constituent alters the lattice size and consequently inflicts an internal pressure on the system.

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

We introduce a new classical spin liquid on the pyrochlore lattice by extending spin ice with further neighbour interactions. This disorder-free spin model exhibits a form of dynamical heterogeneity with extremely slow relaxation for some spins while others fluctuate quickly down to zero temperature. We thus call this state "spin slush", in analogy to the heterogeneous mixture of solid and liquid water.

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

In this talk, I will describe a new technique—stochastic resonance magnetic force microscopy (SRMFM)—developed in my group for imaging the vortex dynamics in multiply connected superconducting devices. Unlike existing techniques, which directly image vortices, our technique relies on the mechanism of stochastic resonance to image the fluctuations between different vortex configurations.

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

The kagome lattice in a mineral compound "Herbertsmithite" represents structurally the most ideal kagome Heisenberg antiferromagnet known to date. Herbertsmithite does not undergo a magnetic long-range order or spin freezing at least down to ~J/2000. We will present 17-Oxygen and 2-Deuterium single crystal NMR study of Herbertsmithite. We will demonstrate that the ground state of the kagome plane has a spin gap ~ 0.05J [1], and ~5% excess Cu2+ ions occupying the out-of-plane Zn2+ sites are the only defects [2].

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

A many-body quantum system on the verge of instability between competing ground states exhibits emergent phenomena. Interacting electrons on triangular lattices are likely subjected to multiple instabilities in the charge and spin degrees of freedom, affording diverse phenomena related to the Mott physics. The molecular conductors are superior model systems for studying the Mott physics because of the designability and controllability of material parameters such as lattice geometry and bandwidth by chemical substitution and/or pressure.

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

In recent years, there has been much interest in honeycomb lattice quantum magnets described by Kitaev-Heisenberg Hamiltonian. For example, honeycomb lattice iridates, such as Na2IrO3 and Li2IrO3 have been intensely scrutinized. Recently, we proposed that a 4d honeycomb magnet α-RuCl3 is a promising candidate material in which Kitaev physics could be studied. I will give an overview of the physics of alpha-RuCl3, and talk about recent experimental and theoretical advances.

Scientific Areas: 
 

 

Thursday May 12, 2016
Speaker(s): 

We have recently demonstrated an experimental platform to isolate 2D materials that are unstable in the ambient environment. I will discuss our recent studies of the charge density wave compound 1T-TaS2 and superconducting 2H-NbSe¬ in the atomically thin limit, made possible using this technique. In TaS2, we uncover a new surface charge density wave transition that is distinct from that in the bulk layers, as well as demonstrate continuous electrical control over this phase transition.

Scientific Areas: 
 

 

Thursday May 12, 2016

Beyond their deceptively featureless ground states, spin liquids are particularly remarkable in the exotic nature of their (fractionalised and gauge charged) excitations. Quenched disorder can be instrumental in nucleating or localising defects with unusual properties, revealing otherwise hidden features of these topological many-body states. This talk discusses how to turn the nuisance of disorder into a powerful probe and origin of new collective behaviour.

Scientific Areas: 

Scientific Organizer:

  • Michel Gingras, University of Waterloo