Hybrid Nodal-chain Semimetal State in MgCaN2

Autor:	Wu, Hongbo, Ma, Da-Shuai, Fu, Botao
Rok vydání:	2023
Předmět:	Condensed Matter - Materials Science Condensed Matter - Mesoscale and Nanoscale Physics hybrid Nodal-chain semimetal band tilting effect flat-band first-principles calculations
Druh dokumentu:	Working Paper
Popis:	The distinct over-tilting of band crossings in topological semimetal generates the type-I and typeII classification of Dirac/Weyl and nodal-line fermions, accompanied by the exotic electronic and magnetic transport properties. In this work, we propose a concept of hybrid nodal-chain semimetal, which is identified by the linked type-I and type-II nodal rings in the Brillouin zone. Based on first-principles calculations and swarm-intelligence structure search technique, a new ternary nitride MgCaN2 crystal is proposed as the first candidate to realize a novel 3D hybrid nodal-chain state. Remarkably, a flat band is emergent as a characteristic signature of such a hybrid nodal-chain along certain direction in the momentum space, thereby serving a platform to explore the interplay between topological semimetal state and flat band. Moreover, the underlying protection mechanism of the hybrid nodal-chain is revealed by calculating the mirror Z2 invariant and developing a k.p effective Hamiltonian. Additionally, considerable drumhead-like surface states with unique connection patterns are illustrated to identify the non-trivial band topology, which may be measured by future experiments. Comment: 9 pages, 6 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/2301.03037 Zobrazit plný text záznamu View this record from Arxiv