Sliding Ferroelectricity in Rhombohedral MoS2: A New Approach to Nonvolatilely Switch the Interaction between Light and Matter

Event Date:
2024-09-12T10:00:00
2024-09-12T11:00:00
Event Location:
AMPEL 311
Speaker:
Ziliang Ye, University of British Columbia
Related Upcoming Events:
Condensed Matter Seminars
Intended Audience:
Graduate
Local Contact:

Josh Folk (jfolk@physics.ubc.ca)

Event Information:

Abstract:

The tunability in the stacking of layered materials with van der Waals bonding provides a new and powerful approach to engineer their physical properties. Sliding ferroelectricity is one such example where an electric field drives one layer of materials to move relative to its neighbours due to an out-of-plane electric polarization arising from interlayer coupling. Sliding ferroelectricity can therefore occur in traditionally non-ferroelectric materials and has been observed in artificially stacked boron nitrides and transition metal dichalcogenides (TMDs). In this talk, I will show that such a hysteric phenomenon can occur in chemically synthesized rhombohedral molybdenum disulfide (3R-MoS2) crystals with pre-existing domain walls. I will first discuss our studies on domain characterization using photocurrent and scanning probe microscopy. I will then show that these polarization domains and their switching behavior can be probed by optical spectroscopy, revealing the existence of a variety of switching pathways. Due to their strong excitonic effects and sliding ferroelectricity, rhombohedral TMDs can be built into nonvolatile optical memories with high performances. 

Bio:

We are an optical spectroscopy group studying light matter interaction in low-dimensional materials. We are currently focused on exploring how topology, correlation effects, and other emergent degrees of freedom interact with each other in two-dimensional van der Waals materials such as graphene, phosphorene, transition metal dichalcogenide, hexagonal boron nitride, high-Tc cuprates and their heterostructures. Our expertise includes ultrafast optical spectroscopy with diffraction-limited resolution at low temperatures and strong magnetic fields as well as nearfield optical microscopy. In the past, we have utilized ultrafast nonlinear optical spectroscopies to reveal the crystal and electronic structure of TMDCs. We are currently interested in developing novel optical microscopy techniques to interrogate the 2D material’s intrinsic response and to control them with the strong optical field provided by coherent laser light. In the meantime, novel devices based on bulk photovoltaic effect and topological superconductivity are being actively explored in the group for classical and quantum applications.

Learn More:

Add to Calendar 2024-09-12T10:00:00 2024-09-12T11:00:00 Sliding Ferroelectricity in Rhombohedral MoS2: A New Approach to Nonvolatilely Switch the Interaction between Light and Matter Event Information: Abstract: The tunability in the stacking of layered materials with van der Waals bonding provides a new and powerful approach to engineer their physical properties. Sliding ferroelectricity is one such example where an electric field drives one layer of materials to move relative to its neighbours due to an out-of-plane electric polarization arising from interlayer coupling. Sliding ferroelectricity can therefore occur in traditionally non-ferroelectric materials and has been observed in artificially stacked boron nitrides and transition metal dichalcogenides (TMDs). In this talk, I will show that such a hysteric phenomenon can occur in chemically synthesized rhombohedral molybdenum disulfide (3R-MoS2) crystals with pre-existing domain walls. I will first discuss our studies on domain characterization using photocurrent and scanning probe microscopy. I will then show that these polarization domains and their switching behavior can be probed by optical spectroscopy, revealing the existence of a variety of switching pathways. Due to their strong excitonic effects and sliding ferroelectricity, rhombohedral TMDs can be built into nonvolatile optical memories with high performances.  Bio: We are an optical spectroscopy group studying light matter interaction in low-dimensional materials. We are currently focused on exploring how topology, correlation effects, and other emergent degrees of freedom interact with each other in two-dimensional van der Waals materials such as graphene, phosphorene, transition metal dichalcogenide, hexagonal boron nitride, high-Tc cuprates and their heterostructures. Our expertise includes ultrafast optical spectroscopy with diffraction-limited resolution at low temperatures and strong magnetic fields as well as nearfield optical microscopy. In the past, we have utilized ultrafast nonlinear optical spectroscopies to reveal the crystal and electronic structure of TMDCs. We are currently interested in developing novel optical microscopy techniques to interrogate the 2D material’s intrinsic response and to control them with the strong optical field provided by coherent laser light. In the meantime, novel devices based on bulk photovoltaic effect and topological superconductivity are being actively explored in the group for classical and quantum applications. Learn More: Ziliang's Investigator biography page at the Stewart Blusson Quantum Matter Institute: Ziliang Ye - Stewart Blusson Quantum Matter Institute (ubc.ca) Ziliang's faculty page for the Department of Physics & Astronomy: zlye | UBC Physics & Astronomy   Event Location: AMPEL 311