Electric-Field Control of Terahertz Response via Spin-Corner-Layer Coupling in Altermagnetic Bilayers

Fuente: arXiv
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Main Authors: Wang, Jianhua, Han, Yilin, Qian, Shifeng, Cheng, Zhenxiang, Wang, Wenhong, Yu, Zhi-Ming, Wang, Xiaotian
Format: Preprint
Published: 2025
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author Wang, Jianhua
Han, Yilin
Qian, Shifeng
Cheng, Zhenxiang
Wang, Wenhong
Yu, Zhi-Ming
Wang, Xiaotian
author_facet Wang, Jianhua
Han, Yilin
Qian, Shifeng
Cheng, Zhenxiang
Wang, Wenhong
Yu, Zhi-Ming
Wang, Xiaotian
contents Electric field control of electron charge and spin degrees of freedom is fundamental to modern semiconductor and spintronic devices. Yet controlling electromagnetic waves with an electric field, particularly in the terahertz (THz) band, remains a challenge. Here, we propose a spin-corner-layer coupling (SCLC) mechanism in second-order topological altermagnetic bilayers. By using an electric field to influence electrons between different layers, the SCLC mechanism enables simultaneous control over corner and spin degrees of freedom, thereby allowing electric-field tuning of the absorption, emission intensity, and even polarization of THz waves. Taking bilayer NiZrI$_6$ nanodisks as a prototype, we demonstrate that an ultralow electrostatic field can switch both the spin and the layer polarizations of corner states. This dual switching modulates transition dipole moments and oscillator strengths between different corner states, thereby enabling the manipulation of THz waves. This study establishes a mechanism for the electric-field control of spin and THz waves through SCLC, yielding important implications for the advancement of THz spintronics.
format Preprint
id arxiv_https___arxiv_org_abs_2509_13643
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Electric-Field Control of Terahertz Response via Spin-Corner-Layer Coupling in Altermagnetic Bilayers
Wang, Jianhua
Han, Yilin
Qian, Shifeng
Cheng, Zhenxiang
Wang, Wenhong
Yu, Zhi-Ming
Wang, Xiaotian
Materials Science
Electric field control of electron charge and spin degrees of freedom is fundamental to modern semiconductor and spintronic devices. Yet controlling electromagnetic waves with an electric field, particularly in the terahertz (THz) band, remains a challenge. Here, we propose a spin-corner-layer coupling (SCLC) mechanism in second-order topological altermagnetic bilayers. By using an electric field to influence electrons between different layers, the SCLC mechanism enables simultaneous control over corner and spin degrees of freedom, thereby allowing electric-field tuning of the absorption, emission intensity, and even polarization of THz waves. Taking bilayer NiZrI$_6$ nanodisks as a prototype, we demonstrate that an ultralow electrostatic field can switch both the spin and the layer polarizations of corner states. This dual switching modulates transition dipole moments and oscillator strengths between different corner states, thereby enabling the manipulation of THz waves. This study establishes a mechanism for the electric-field control of spin and THz waves through SCLC, yielding important implications for the advancement of THz spintronics.
title Electric-Field Control of Terahertz Response via Spin-Corner-Layer Coupling in Altermagnetic Bilayers
topic Materials Science
url https://arxiv.org/abs/2509.13643