近日，新加坡南洋理工大学的Baile Zhang及其研究团队取得一项新进展。经过不懈努力，他们对光子轴子绝缘体进行研究
该研究团队在三维光子晶体中实现了轴子绝缘体，并对其拓扑性质进行了探究。所展示的特性包括：每个表面具有半量子化的陈数，类似于分数量子陈绝缘体；形成三维拓扑传输的单向手性铰链态；以及分数量子陈数与整数量子陈数之间的算术运算。这项研究工作从实验上确立了轴子绝缘体作为一种三维拓扑物质相，并使得手性态能够通过编织形成复杂、单向的三维网络。
据悉，轴子是一种假设中的基本粒子，在自然界中尚未被探测到，但它可以在被称为轴子绝缘体的三维晶体中以准粒子的形式出现。以往的轴子绝缘体实现大多局限于二维系统，因此其在三维空间中的拓扑性质在实验中尚未得到探索。
附：英文原文
Title: Photonic axion insulator
Author: Gui-Geng Liu, Subhaskar Mandal, Xiang Xi, Qiang Wang, Chiara Devescovi, Antonio Morales-Pérez, Ziyao Wang, Linyun Yang, Rimi Banerjee, Yang Long, Yan Meng, Peiheng Zhou, Zhen Gao, Yidong Chong, Aitzol García-Etxarri, Maia G. Vergniory, Baile Zhang
Issue&Volume: 2025-01-10
Abstract: Axions, hypothetical elementary particles that remain undetectable in nature, can arise as quasiparticles in three-dimensional crystals known as axion insulators. Previous implementations of axion insulators have largely been limited to two-dimensional systems, leaving their topological properties in three dimensions unexplored in experiment. Here, we realize an axion insulator in a three-dimensional photonic crystal and probe its topological properties. Demonstrated features include half-quantized Chern numbers on each surface that resembles a fractional Chern insulator, unidirectional chiral hinge states forming topological transport in three dimensions, and arithmetic operations between fractional and integer Chern numbers. Our work experimentally establishes the axion insulator as a three-dimensional topological phase of matter and enables chiral states to form complex, unidirectional three-dimensional networks through braiding.
DOI: https://www.science.org/doi/10.1126/science.adr5234
Source: https://www.science.org/doi/10.1126/science.adr5234