Condensed Matter Seminar

Abstract: Understanding the drift of the Josephson junction resistance after ABAA trimming is critical for targeting for large scale processes. In this talk we address the dynamics of the resistance change from short-term to long-term effects. We report the sudden changes due to the voltage application and removal and track the longer term drift as the junctions settle. The differences between nominally identical junctions are identified and time scales for the divergences between the trimmed values are reported.

Abstract: Nontrivial topological defects such as knotted solitons called hopfions have been observed in a variety of materials including chiral magnets, nematic liquid crystals and even in ferroelectrics as well as studied in other physical contexts such as Bose-Einstein condensates.  These topological entities can be modeled using the relevant physical variable, e.g., magnetization, polarization or the director field.  Specifically, we find exact static soliton solutions for the unit spin vector field of an inhomogeneous, anisotropic three-dimensional (3D) Heisenberg ferro

Abstract: Photocathodes—materials that convert photons into electrons through the photoelectric effect (explained by Einstein)—are important for many modern technologies that rely on light detection or electron-beam generation. However, existing photocathode materials have become increasingly difficult to meet the performance requirements of related cutting-edge technology upgrades. Most of these materials, and the theory (Spicer’s three-step model) to understand their photoemission properties, were discovered and established more than 60 years ago.

Abstract: Time-reversed pairs of topological bands with opposite Chern numbers are commonly found in moiré superlattices based on transition metal dichalcogenides. Recent experimental breakthroughs have demonstrated that these topological bands provide a rich platform for realizing fractional quantum matter at zero external magnetic fields.

Abstract: Lithium-ion battery is featured by structural and chemical complexities across a broad range of length scales and, ultimately, it is the hierarchy of the battery structure that determines its functionality. Investigating battery function, degradation, and failure mechanisms requires a comprehensive exploration encompassing structural, chemical, mechanical, and dynamic perspectives.

Abstract: The Hall effect [1] is widely used to probe the electronic structure of materials and has found applications in various electronic devices. Research on the Hall effect has expanded to include related phenomena such as the anomalous Hall effect, the spin Hall effect, and the quantum Hall effect. More recently, these studies have been extended to the nonlinear regime [2].

Abstract: The antiferromagnetic ground state of the two-dimensional Hubbard model on a square lattice at half-filling was shown to become ferromagnetic with the addition of a single hole for infinite e-e repulsion (Nagaoka, 1966). However, Nagaoka ferromagnetism has not been seen in naturally occurring solid-state materials. The advent of synthetic platforms - atoms in optical lattices, and quantum dots/dopant clusters in semiconductors has led us to study Hubbard-like models on large finite lattices using DMRG techniques.

Abstract: I will present experimental studies on the topological and correlated properties of monolayer TaIrTe4. First, I will discuss a dual quantum spin Hall (QSH) insulator, arising from the interplay between its single-particle topology and density-tuned correlations. At charge neutrality, monolayer TaIrTe4 exhibits QSH insulator behavior, characterized by enhanced nonlocal transport and quantized helical edge conductance.

Abstract: The observation of superconductivity and correlated insulators in magic-angle graphene has ushered in the new paradigm of moiré materials, where two-dimensional materials are stacked and rotated to generate a variety of intriguing phases of quantum matter. Such physics is enabled by the confluence of band structure engineering, strong interactions, and electronic topology.

[EQI] Eddleman Quantum Institute Seminar Series