Seminar
- Tuesday 12:30-13:30
- Room L1-029
- Each seminar will feature one or two 30 min talks by members of the CMP group about their research. This is a fantastic opportunity to get to know your fellow CMP colleagues and start collaborations. Occasionally we also host invited speakers.
Schedule Winter 2025
- Apr 22, 2025
Sarah Burke (UBC)
"Square and not-so-square nets: The interplay of topology and symmetry in non-
symmorphic square-net tellurides probed by Scanning Tunnelling Microscopy"
The non-symmorphic square-net materials feature symmetry enforced band crossings
that give rise to Dirac nodal loops and both topologically trivial and non-trivial surface
states. These materials, in the P4/nmm space group, host a plane of atoms in a square
ne (e.g. Si in the ZrSiX family, or Sb in the RESbX family) with a 2-atom unit cell. This
2-atom square lattice, along with glide plane symmetry enforces a degeneracy at the
edge of the Brillouin zone driving a crossing of bands with orthogonal orbital symmetry
preventing hybridization. These features give rise to wide-bandwidth linear crossings
that revolve around the Brillouin zone enclosing regions of distinct topology.
I will describe scanning tunnelling microscopy (STM), scanning tunnelling spectroscopy
(STS) and quasiparticle interference (QPI) results on two such square net materials:
ZrSiTe which maintains a robust square net structure and exhibits a topologically non-
trivial drumhead surface state [1,2], and LaSbTe which features a distorted
orthorhombic structure with broken glide symmetry at the stoichiometric composition.
This allows a comparison of the impact of weak (spin-orbit coupling in ZrSiTe) and
strong (symmetry in o-LaSbTe) perturbations to the topology. In ZrSiTe, while SO opens
a gap in the nodal loops, the drumhead state persists. In contrast, breaking the
underlying symmetry that protects the nodal loop (perhaps somewhat obviously) breaks
the topology, however the appearance of tetragonal regions in twin boundaries and the
influence of surface doping [3] on the structure of LaSbTe indicate the coupled structure,
electronic states, and therefore topology may be malleable in this material and subject
to strain and other external tuning knobs.
References
[1] L. Muechler, et al. PRX 10, 011026 (2020)
[2] B. Stuart, et al. PRB 105, L121111 (2022)
[3] J. Bannies, et al. (2025) https://arxiv.org/abs/2407.08798
- Apr 8, 2025
Albion Arifi (Boettcher Group)
"Dirac Zero Modes and the Chiral Anomaly for Multifold Fermions in Topological Semimetals"
- Mar 11, 2025
Tomas Bzdusek (University of Zurich)
Joint with TPI seminar
Schedule Fall 2024
- Dec 10, 2024
Akila Bandara (Charlebois Group)
"Magnetic Field Platforms and Yeast Magnetobiology"
- Dec 3, 2024
Ronny Thomale (University of Wuerzburg)
"The New Frontier of Topological Phases - Collective Phenomena in Synthetic Matter "
Joint with TPI seminar
- Nov 12, 2024
no seminar (reading week)
- Nov 5, 2024
Marvin Hirschel (Davis Group)
"Listening to the sound of dark matter with superfluid helium"
- Oct 29, 2024
Kiril Max Kolevski (Boninsegni Group)
"Superfluidity of quasi-2D He-4 droplets on graphite"
- Oct 22, 2024
Charles Jensen (Hegmann Group)
"Terahertz spectroscopy of semiconductor nanomaterials"
- Oct 15, 2024
Nils Refvik (Hegmann Group)
"Probing semiconductor photoconductivity with terahertz spectroscopy"
- Oct 8, 2024
Special TPI Seminar: Eric Woolgar (University of Alberta)
Schedule Winter 2024
- May 29, 2024
Pramodh Senarath Yapa (University of Innsbruck)
"How solid is a dipolar supersolid?"
- April 30, 2024
Furkan Altincicek (Wolkow Group)
"Silicon Dimers on the Hydrogenated Surface"
- April 23, 2024
Arina Tashchilina (LeBlanc Group)
"Quantum computation and simulation with neutral atoms"
- April 16, 2024
Daniiar Zhaguparov (Woodside Group)
"Mechanical stability of exoribonuclease-resistant RNA (xrRNA) from Zika virus"
- April 9, 2024
Pablo Basteiro (University of Wuerzburg)
"Entanglement in interacting Majorana chains and transitions of von Neumann algebras"
Joint with TPI seminar
- April 2, 2024
Albion Arifi (Boettcher Group)
"Topological Semimetals: Unraveling their Unconventional Electromagnetic Response"
- March 26, 2024
Max Yuan (Wolkow Group)
"Silicon dangling bond wires and the path towards atomic electronics"
- March 19, 2024:
Sam Yu (Boninsegni Group)
"Possible superfluid phase of helium on graphene: Quantum Monte Carlo study"
- March 12, 2024
Eran Ginossar (University of Surrey)
"Protection of quantum information in a chain of Josephson junctions: the Magenium qubit"
- March 5, 2024
no seminar (March Meeting)
- February 27, 2024
no seminar
- February 20, 2024
no seminar (reading week)
- February 13, 2024
James Maldaner (LeBlanc/Porat Group)
"Feasibility Analysis of a Proposed Test of Quantum Gravity via Novel Optical Magnetometry in Xenon"
- February 6, 2024
Rohith Vedhthaanth Sekar (Woodside Group)
"The role of computational biophysics in COVID-19 drug discovery (..at the Woodside lab)"
- January 30, 2024
Katryna Fast (Freeman Group)
"Einstein-de Haas torque as a discrete spectroscopic probe allows nanomechanical measurement of a magnetic resonance"
- January 23, 2024
Igor Boettcher
"Holography on a chip"
Past Schedule
- April 13, 2023 online
David Moser (Technical University Dresden)
"Quasiuniversality from all-in-all-out Weyl quantum criticality in pyrochlore iridates"
- March 23, 2023
Santanu Dey (Maciejko group)
"Field-driven transition from quantum spin liquid to symmetry-breaking order in triangular-lattice antiferromagnets"
- March 16, 2023
Frank Marsiglio
What some of my undergraduate students did in the summer (circa 2015-2016)*
- March 9, 2023
Michael Buchhold (University of Cologne)
"Measurement-Induced Phase Transitions of Fermions: Phenomenology, Effective Theory and Strategies to Reveal Them"
- Feburary 23, 2023
No seminar (reading week)
- Feburary 9, 2023
Igor Herbut (Simon Fraser University)
"Multiband superconductivity and breaking of time-reversal symmetry: theory of Bogoliubov-Fermi surfaces"
- Feburary 2, 2023
Javad Shabani (New York University)
"Towards realization of protected qubits using topological superconductivity"
Robert Wolkow
"An Introduction to Atom-Defined Silicon Quantum Devices and Ultra-Fast, Ultra-Low Power Classical Circuits"
- November 17, 2022
Howe Simpson (Hegmann Group)
"Measuring Ultrafast Dynamics on the Nanoscale: The Terahertz Scanning Tunneling Microscope"
- November 10, 2022
no seminar (reading week)
- November 3, 2022
Shankar Ganesh (Maciejko Group)
"Describing transitions between topological and conventional symmetry-broken phases"
- October 27, 2022
Alexander Shook (Davis Group)
"Novel Properties of Superfluid 3He Under Nanoscale Confinement"
- October 20, 2022
Michael Dunsmore (Freeman Group)
"Three Axis Torque Investigation of Interfacial Exchange Coupling in a NiFe/CoO Bilayer Magnetic Disk"
- October 13, 2022
no seminar
- October 6, 2022
Canon Sun (Maciejko/Boettcher Group)
"SO(2) theory of confined superfluid He-3"
- September 29, 2022
Phong Nguyen (Boninsegni Group)
"Dimensional Crossovers in 2D superfluids"
- September 22, 2022
Santanu Dey (Maciejko Group)
"Quantum-critical electrodynamics of Luttinger fermions"
- December 9, 2021
Aaron Lyons (Woodside Group)
"Characterisation of Non-Productive Attempts at Structural Assembly in Single Biomolecules"
- November 18, 2021
Logan Cooke (LeBlanc Group)
"Holonomic Quantum Computing in Ultracold Neutral Atoms via Floquet Engineering"
- November 4, 2021
Pramodh Senarath Yapa (Marsiglio/Maciejko Group)
"Creating a Superfluid Crystal in Helium-3"
- October 28, 2021
Clinton Potts (Davis Group)
"Dynamical Backaction Magnomechanics"
- October 21, 2021
Mason Protter (Marsiglio/Maciejko Group)
"Non-Abelian gauge structure in driven quantum gasses"
- October 14, 2021
Max Yuan (Wolkow Group)
"Towards the atomic scale readout of acceptor states in p-doped Si"
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