Tunable moiré materials for probing Berry physics and topology

PC Adak, S Sinha, A Agarwal… - Nature Reviews Materials, 2024 - nature.com
Berry curvature physics and quantum geometric effects have been instrumental in
advancing topological condensed matter physics in recent decades. Although Landau level …

Topological Bound on the Structure Factor

Y Onishi, L Fu - Physical Review Letters, 2024 - APS
We show that the static structure factor of general many-body systems with U (1) symmetry
has a lower bound determined only by the ground state Chern number. Our bound relies …

Quantum Geometry in Quantum Materials

J Yu, BA Bernevig, R Queiroz, E Rossi, P Törmä… - arxiv preprint arxiv …, 2024 - arxiv.org
Quantum geometry, characterized by the quantum geometric tensor, is pivotal in diverse
physical phenomena in quantum materials. In condensed matter systems, quantum …

Universal relation between energy gap and dielectric constant

Y Onishi, L Fu - Physical Review B, 2024 - APS
We establish a universal relation between the energy gap and the static dielectric constant
for all insulating states. This relation yields an upper bound on the energy gap, which only …

Accessing bands with extended quantum metric in kagome Cs2Ni3S4 through soft chemical processing

G Villalpando, M Jovanovic, B Hoff, Y Jiang… - Science …, 2024 - science.org
Flat bands that do not merely arise from weak interactions can produce exotic physical
properties, such as superconductivity or correlated many-body effects. The quantum metric …

Corner Charge Fluctuation as an Observable for Quantum Geometry and Entanglement in Two-Dimensional Insulators

PM Tam, J Herzog-Arbeitman, J Yu - Physical Review Letters, 2024 - APS
Measuring bipartite fluctuations of a conserved charge, such as the particle number, is a
powerful approach to understanding quantum systems. When the measured region has …

Probing Berry curvature in magnetic topological insulators through resonant infrared magnetic circular dichroism

SK Bac, F Le Mardelé, J Wang, M Ozerov… - Physical Review Letters, 2025 - APS
Probing the quantum geometry and topology in condensed matter systems has relied
heavily on static electronic transport experiments in magnetic fields. Yet, contact-free optical …

Detecting the spread of valence-band Wannier functions by optical sum rules

LF Cárdenas-Castillo, S Zhang, FL Freire Jr, D Kochan… - Physical Review B, 2024 - APS
The spread of valence-band Wannier functions in semiconductors and insulators is a
characteristic property that gives a rough estimation of how insulating is the material. We …

Conductivity in flat bands from the Kubo-Greenwood formula

KE Huhtinen, P Törmä - Physical Review B, 2023 - APS
Conductivity in a multiband system can be divided into intra-and interband contributions,
and the latter further into symmetric and antisymmetric parts. In a flat band, intraband …

Quantum weight

Y Onishi, L Fu - arxiv preprint arxiv:2406.06783, 2024 - arxiv.org
We introduce the concept of quantum weight as a fundamental property of quantum many-
body systems that is encoded in the ground-state static structure factor and characterizes …