Topological Interstitial-Electron Conductor

Fuente: arXiv
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Main Authors: He, Tingli, Zhang, Xiaoming, Cui, Chaoxi, Han, Yilin, Wang, Yang, Jiang, Wei, Yu, Zhi-Ming, Yao, Yugui
Format: Preprint
Published: 2026
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author He, Tingli
Zhang, Xiaoming
Cui, Chaoxi
Han, Yilin
Wang, Yang
Jiang, Wei
Yu, Zhi-Ming
Yao, Yugui
author_facet He, Tingli
Zhang, Xiaoming
Cui, Chaoxi
Han, Yilin
Wang, Yang
Jiang, Wei
Yu, Zhi-Ming
Yao, Yugui
contents Electron transport in solids arises primarily from two mechanisms: freely moving bulk electrons in metals, and gapless boundary states in topological insulators. Here, we report a new mechanism discovered in electrides. The topological interstitial-electron conductors (TIECs) proposed here are insulating electrides, but host interstitial electrons (IEs) distributed within crystal voids that traverse the entire unit cell. Without being tightly bound to real ions, the IEs generally experience low periodic potential barrier along the void channels. As a consequence, by applying a weak electric field sufficient to overcome the IE barriers but far below the system's dielectric breakdown threshold, one can expect that the TIECs would generate a persistent current contributed by the IEs and propagating along the void channels. We identify a family of realistic altermagnetic electrides, $A_5X_3$ ($A$ = Ca, Sr, Ba, Yb; $X$ = As, Sb), as TIECs. Remarkably, for $A_5X_3$ materials, the periodic potential barrier of the IEs along the void channels are ultralow, ranging from 13.43 to 67.96 meV per formula unit. This renders our proposal readily accessible to experimental verification. We further demonstrate that when the IEs of $A_5X_3$ undergo periodic motion along the channels, topological surface states will emerge at the boundary perpendicular to the channel direction, and continuously move across the bulk band gap. This pumping-like behaviour not only corroborates the topological nature of TIECs, but also rationalizes the finite-electric-field induced electronic transport within the band theory. Our findings expand the classification of electronic conductors, uncover unexplored transport properties of electrides, and establish a new material platform for low-power electronic devices.
format Preprint
id arxiv_https___arxiv_org_abs_2605_31195
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Topological Interstitial-Electron Conductor
He, Tingli
Zhang, Xiaoming
Cui, Chaoxi
Han, Yilin
Wang, Yang
Jiang, Wei
Yu, Zhi-Ming
Yao, Yugui
Materials Science
Electron transport in solids arises primarily from two mechanisms: freely moving bulk electrons in metals, and gapless boundary states in topological insulators. Here, we report a new mechanism discovered in electrides. The topological interstitial-electron conductors (TIECs) proposed here are insulating electrides, but host interstitial electrons (IEs) distributed within crystal voids that traverse the entire unit cell. Without being tightly bound to real ions, the IEs generally experience low periodic potential barrier along the void channels. As a consequence, by applying a weak electric field sufficient to overcome the IE barriers but far below the system's dielectric breakdown threshold, one can expect that the TIECs would generate a persistent current contributed by the IEs and propagating along the void channels. We identify a family of realistic altermagnetic electrides, $A_5X_3$ ($A$ = Ca, Sr, Ba, Yb; $X$ = As, Sb), as TIECs. Remarkably, for $A_5X_3$ materials, the periodic potential barrier of the IEs along the void channels are ultralow, ranging from 13.43 to 67.96 meV per formula unit. This renders our proposal readily accessible to experimental verification. We further demonstrate that when the IEs of $A_5X_3$ undergo periodic motion along the channels, topological surface states will emerge at the boundary perpendicular to the channel direction, and continuously move across the bulk band gap. This pumping-like behaviour not only corroborates the topological nature of TIECs, but also rationalizes the finite-electric-field induced electronic transport within the band theory. Our findings expand the classification of electronic conductors, uncover unexplored transport properties of electrides, and establish a new material platform for low-power electronic devices.
title Topological Interstitial-Electron Conductor
topic Materials Science
url https://arxiv.org/abs/2605.31195