Non-Hermitian Boundary in a Surface Selective Reconstructed Magnetic Weyl Semimetal
(2025) In Advanced Materials 37(14).- Abstract
Non-Hermitian physics, studying systems described by non-Hermitian Hamiltonians, reveals unique phenomena not present in Hermitian systems. Unlike Hermitian systems, non-Hermitian systems have complex eigenvalues, making their effects less directly observable. Recently, significant efforts have been devoted to incorporating the non-Hermitian effects into condensed matter physics. However, progress is hindered by the absence of a viable experimental approach. Here, the discovery of the surface-selectively spontaneous reconstructed Weyl semimetal NdAlSi provides a feasible experimental platform for studying non-Hermitian physics. Utilizing angle-resolved photoemission spectroscopy (ARPES) measurements, surface-projected density functional... (More)
Non-Hermitian physics, studying systems described by non-Hermitian Hamiltonians, reveals unique phenomena not present in Hermitian systems. Unlike Hermitian systems, non-Hermitian systems have complex eigenvalues, making their effects less directly observable. Recently, significant efforts have been devoted to incorporating the non-Hermitian effects into condensed matter physics. However, progress is hindered by the absence of a viable experimental approach. Here, the discovery of the surface-selectively spontaneous reconstructed Weyl semimetal NdAlSi provides a feasible experimental platform for studying non-Hermitian physics. Utilizing angle-resolved photoemission spectroscopy (ARPES) measurements, surface-projected density functional theory (DFT) calculations, and scanning tunneling microscopy (STM) measurements, it is demonstrated that surface reconstruction in NdAlSi alters surface Fermi arc (SFA) connectivity and generates new isolated non-topological SFAs (NTSFAs) by introducing non-Hermitian terms. The surface-selective spontaneous reconstructed Weyl semimetal NdAlSi can be viewed as a Hermitian bulk – non-Hermitian boundary system. The isolated non-topological SFAs on the reconstructed surface act as a loss mechanism and open boundary condition (OBC) for the topological electrons and bulk states, serving as non-Hermitian boundary states. This discovery provides a good experimental platform for exploring new physical phenomena and potential applications based on boundary non-Hermitian effects, extending beyond purely mathematical concepts. Furthermore, it provides important enlightenment for constructing topological photonic crystals with surface reconstruction and studying their topological properties.
(Less)
- author
- organization
- publishing date
- 2025-04
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- non-hermitian boundary, surface reconstructed, Weyl semimetal
- in
- Advanced Materials
- volume
- 37
- issue
- 14
- article number
- 2419559
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- scopus:105002264586
- pmid:39910893
- ISSN
- 0935-9648
- DOI
- 10.1002/adma.202419559
- language
- English
- LU publication?
- yes
- id
- 3e60185b-3719-44c2-8ccc-4c948d8365d3
- date added to LUP
- 2025-08-08 09:41:12
- date last changed
- 2025-08-09 03:00:02
@article{3e60185b-3719-44c2-8ccc-4c948d8365d3,
abstract = {{<p>Non-Hermitian physics, studying systems described by non-Hermitian Hamiltonians, reveals unique phenomena not present in Hermitian systems. Unlike Hermitian systems, non-Hermitian systems have complex eigenvalues, making their effects less directly observable. Recently, significant efforts have been devoted to incorporating the non-Hermitian effects into condensed matter physics. However, progress is hindered by the absence of a viable experimental approach. Here, the discovery of the surface-selectively spontaneous reconstructed Weyl semimetal NdAlSi provides a feasible experimental platform for studying non-Hermitian physics. Utilizing angle-resolved photoemission spectroscopy (ARPES) measurements, surface-projected density functional theory (DFT) calculations, and scanning tunneling microscopy (STM) measurements, it is demonstrated that surface reconstruction in NdAlSi alters surface Fermi arc (SFA) connectivity and generates new isolated non-topological SFAs (NTSFAs) by introducing non-Hermitian terms. The surface-selective spontaneous reconstructed Weyl semimetal NdAlSi can be viewed as a Hermitian bulk – non-Hermitian boundary system. The isolated non-topological SFAs on the reconstructed surface act as a loss mechanism and open boundary condition (OBC) for the topological electrons and bulk states, serving as non-Hermitian boundary states. This discovery provides a good experimental platform for exploring new physical phenomena and potential applications based on boundary non-Hermitian effects, extending beyond purely mathematical concepts. Furthermore, it provides important enlightenment for constructing topological photonic crystals with surface reconstruction and studying their topological properties.</p>}},
author = {{Li, Cong and Wang, Yang and Zhang, Jianfeng and Liu, Guowei and Liu, Hongxiong and Chen, Wanyu and Deng, Hanbin and Ma, Wenbo and Polley, Craig and Thiagarajan, Balasubramanian and Kim, Timur K. and Yin, Jiaxin and Shi, Youguo and Xiang, Tao and Tjernberg, Oscar}},
issn = {{0935-9648}},
keywords = {{non-hermitian boundary; surface reconstructed; Weyl semimetal}},
language = {{eng}},
number = {{14}},
publisher = {{John Wiley & Sons Inc.}},
series = {{Advanced Materials}},
title = {{Non-Hermitian Boundary in a Surface Selective Reconstructed Magnetic Weyl Semimetal}},
url = {{http://dx.doi.org/10.1002/adma.202419559}},
doi = {{10.1002/adma.202419559}},
volume = {{37}},
year = {{2025}},
}