The dynamical axion field is a new state of quantum matter where the magnetoelectric response couples strongly to its low-energy magnetic fluctuations.It is fundamentally different from an axion insulator with a stati...The dynamical axion field is a new state of quantum matter where the magnetoelectric response couples strongly to its low-energy magnetic fluctuations.It is fundamentally different from an axion insulator with a static quantized magnetoelectric response.The dynamical axion field exhibits many exotic phenomena such as axionic polariton and axion instability.However,these effects have not been experimentally confirmed due to the lack of proper topological magnetic materials.Combining analytic models and first-principles calculations,here we predict a series of van der Waals layered Mn2Bi2Te5-related topological antiferromagnetic materials that could host the long-sought dynamical axion field with a topological origin.We also show that a large dynamical axion field can be achieved in antiferromagnetic insulating states close to the topological phase transition.We further propose the optical and transport experiments to detect such a dynamical axion field.Our results could directly aid and facilitate the search for topological-origin large dynamical axion field in realistic materials.展开更多
In the band theory,first-principles calculations,the tight-binding method and the effective k⋅p model are usually employed to investigate electronic structures of condensed matters.The effective k⋅p model has a compac...In the band theory,first-principles calculations,the tight-binding method and the effective k⋅p model are usually employed to investigate electronic structures of condensed matters.The effective k⋅p model has a compact form with a clear physical picture,and first-principles calculations can give more accurate results.Nowadays,it has been widely recognized to combine the k⋅p model and first-principles calculations to explore topological materials.However,the traditional method to derive the k⋅p Hamiltonian is complicated and time-consuming by hand.We independently developed a programmable algorithm to construct effective k⋅p Hamiltonians for condensed matters.Symmetries and orbitals are used as the input information to produce the one-/two-/three-dimensional k⋅p Hamiltonian in our method,and the open-source code can be directly downloaded online.At last,we also demonstrated the application to MnBi_(2)Te_(4)-family magnetic topological materials.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities(Grant No.020414380149)the Natural Science Foundation of China(Grant Nos.11674165,11834006 and 11774065)+3 种基金the Fok Ying-Tong Education Foundation of China(Grant No.161006)the National Key R&D Program of China(Grant Nos.2016YFA0300703 and 2019YFA0308404)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX04)the Natural Science Foundation of Shanghai(Grant No.19ZR1471400)。
文摘The dynamical axion field is a new state of quantum matter where the magnetoelectric response couples strongly to its low-energy magnetic fluctuations.It is fundamentally different from an axion insulator with a static quantized magnetoelectric response.The dynamical axion field exhibits many exotic phenomena such as axionic polariton and axion instability.However,these effects have not been experimentally confirmed due to the lack of proper topological magnetic materials.Combining analytic models and first-principles calculations,here we predict a series of van der Waals layered Mn2Bi2Te5-related topological antiferromagnetic materials that could host the long-sought dynamical axion field with a topological origin.We also show that a large dynamical axion field can be achieved in antiferromagnetic insulating states close to the topological phase transition.We further propose the optical and transport experiments to detect such a dynamical axion field.Our results could directly aid and facilitate the search for topological-origin large dynamical axion field in realistic materials.
基金Supported by the Fundamental Research Funds for the Central Universities(Grant No.020414380185)the Natural Science Foundation of Jiangsu Province(Grant No.BK20200007)+1 种基金the National Natural Science Foundation of China(Grant Nos.12074181 and 11834006)the Fok Ying-Tong Education Foundation of China(Grant No.161006).
文摘In the band theory,first-principles calculations,the tight-binding method and the effective k⋅p model are usually employed to investigate electronic structures of condensed matters.The effective k⋅p model has a compact form with a clear physical picture,and first-principles calculations can give more accurate results.Nowadays,it has been widely recognized to combine the k⋅p model and first-principles calculations to explore topological materials.However,the traditional method to derive the k⋅p Hamiltonian is complicated and time-consuming by hand.We independently developed a programmable algorithm to construct effective k⋅p Hamiltonians for condensed matters.Symmetries and orbitals are used as the input information to produce the one-/two-/three-dimensional k⋅p Hamiltonian in our method,and the open-source code can be directly downloaded online.At last,we also demonstrated the application to MnBi_(2)Te_(4)-family magnetic topological materials.
