Monolayer van der Waals kagome lattice for high-temperature flat-band physics

@misc{bong2026monolayer,
  title = {{Monolayer van der Waals kagome lattice for high-temperature flat-band physics}},
  author = {Hyungkun Bong and Choongjae Won and Seongyong Lee and Soomin Oh and Phuong X. Nguyen and Raghav Chaturvedi and Sehyun Oh and Jiyong Han and Paul Malinowski and Chad Mowers and Jimin Kim and Sae Hee Ryu and Hyunjong Lee and Jinhyeok Choi and Sangsu Yer and Chris Jozwiak and Aaron Bostwick and Eli Rotenberg and Craig M. Polley and Matthew D. Watson and Timur K. Kim and Heejun Yang and Jieun Lee and Kin Fai Mak and Jie Shan and Jae-Hoon Park and Gil Young Cho and Kyle M. Shen and Mingu Kang},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.24071},
  eprint = {2610.24071},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.24071},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Monolayer van der Waals kagome lattice for high-temperature flat-band physics
AU  - Hyungkun Bong
AU  - Choongjae Won
AU  - Seongyong Lee
AU  - Soomin Oh
AU  - Phuong X. Nguyen
AU  - Raghav Chaturvedi
AU  - Sehyun Oh
AU  - Jiyong Han
AU  - Paul Malinowski
AU  - Chad Mowers
AU  - Jimin Kim
AU  - Sae Hee Ryu
AU  - Hyunjong Lee
AU  - Jinhyeok Choi
AU  - Sangsu Yer
AU  - Chris Jozwiak
AU  - Aaron Bostwick
AU  - Eli Rotenberg
AU  - Craig M. Polley
AU  - Matthew D. Watson
AU  - Timur K. Kim
AU  - Heejun Yang
AU  - Jieun Lee
AU  - Kin Fai Mak
AU  - Jie Shan
AU  - Jae-Hoon Park
AU  - Gil Young Cho
AU  - Kyle M. Shen
AU  - Mingu Kang
PY  - 2026
DA  - 2026/10/16
PB  - arXiv
DO  - 10.48550/arxiv.2610.24071
UR  - https://arxiv.org/abs/2610.24071
AB  - Kagome lattice materials host a remarkably rich landscape of novel quantum phenomena, all arising from the intrinsic interplay of topology, correlation, and frustration. While previous studies have been mostly limited to bulk three-dimensional (3D) kagome crystals, the realization of a true two-dimensional (2D) kagome system has remained a long-standing goal, to unlock fundamentally new physics and engineering pathways inaccessible in 3D systems. In this work, we establish the first ideal 2D monolayer kagome lattices by leveraging a novel and versatile van der Waals (vdW) kagome family, A2T3X4 (A = K, Rb, Cs; T = Ni, Pd, Pt; X = S, Se). Our nano-focused angle-resolved photoemission spectroscopy (nano-ARPES) directly characterizes the electronic structure of A2T3X4 down to the monolayer limit, notably revealing an isolated kagome-derived flat band just below the Fermi level. Via gate-engineering of 2D A2T3X4, the kagome flat band can be further tuned to the Fermi level, allowing direct access to the partially filled flat band physics and establishing a qualitatively new 2D flat band platform. Compared to existing moire-based artificial flat band systems, this vdW kagome-based intrinsic flat band system realizes more than 220 times higher flat band electron density, opening an entirely new density and energy regime for exploring 2D flat band physics. Harnessing this high-electron-density flat band in 2D vdW kagome system provides a clear pathway to scale emergent flat band phenomena - such as fractional quantum anomalous Hall states - to far higher temperatures than currently achievable, as long-envisioned in theory and further supported by our many-body calculations.
ER  -