Anomalous Acoustic Plasmons in Two-Dimensional Over-Tilted Dirac Bands

Chang Xu Yan; Furu Zhang; Chao Yang Tan; Hao Ran Chang; Jianhui Zhou; Yugui Yao

doi:10.1088/0256-307X/43/4/040707

Anomalous Acoustic Plasmons in Two-Dimensional Over-Tilted Dirac Bands

Chang Xu Yan
, Furu Zhang
, Chao Yang Tan
, Hao Ran Chang^*
, Jianhui Zhou^*
, Yugui Yao

^*Corresponding author for this work

Sichuan Normal University
Beijing Forestry University
Chinese Academy of Sciences
Beijing Institute of Technology

Research output: Contribution to journal › Letter › peer-review

Abstract

The over-tilting of Dirac cones has led to various fascinating quantum phenomena. In this study, we demonstrate that the distinct geometry of two-dimensional type-II Dirac cones dictates the emergence of anomalous acoustic plasmons (AAPs) that deviate from that of the conventional (Formula presented) (Formula presented) plasmon. The first AAP originates from the strong hybridization of two pockets with large velocity anisotropy at one Dirac point. The second AAP is attributed to the significant enhancement in band correlation around the open Fermi surface. These plasmons exhibit valley-dependent chirality along the tilting direction caused by chiral electron dispersion. Meanwhile, we discuss the tunability of plasmon dispersion and lifetime by tuning the gap and dielectric substrate. Our work provides a promising framework to generate novel plasmons in Dirac materials.

Original language	English
Journal	Chinese Physics Letters
Volume	43
Issue number	4
DOIs	https://doi.org/10.1088/0256-307X/43/4/040707
Publication status	Published - 1 Apr 2026
Externally published	Yes

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10.1088/0256-307X/43/4/040707

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title = "Anomalous Acoustic Plasmons in Two-Dimensional Over-Tilted Dirac Bands",

abstract = "The over-tilting of Dirac cones has led to various fascinating quantum phenomena. In this study, we demonstrate that the distinct geometry of two-dimensional type-II Dirac cones dictates the emergence of anomalous acoustic plasmons (AAPs) that deviate from that of the conventional (Formula presented) (Formula presented) plasmon. The first AAP originates from the strong hybridization of two pockets with large velocity anisotropy at one Dirac point. The second AAP is attributed to the significant enhancement in band correlation around the open Fermi surface. These plasmons exhibit valley-dependent chirality along the tilting direction caused by chiral electron dispersion. Meanwhile, we discuss the tunability of plasmon dispersion and lifetime by tuning the gap and dielectric substrate. Our work provides a promising framework to generate novel plasmons in Dirac materials.",

author = "Yan, \{Chang Xu\} and Furu Zhang and Tan, \{Chao Yang\} and Chang, \{Hao Ran\} and Jianhui Zhou and Yugui Yao",

note = "Publisher Copyright: {\textcopyright} 2026 Chinese Physical Society and IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved. This article is available under the terms of the https://publishingsupport.iopscience.iop.org/iop-standard/v1.",

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AU - Yan, Chang Xu

AU - Zhang, Furu

AU - Tan, Chao Yang

AU - Chang, Hao Ran

AU - Zhou, Jianhui

AU - Yao, Yugui

N1 - Publisher Copyright: © 2026 Chinese Physical Society and IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved. This article is available under the terms of the https://publishingsupport.iopscience.iop.org/iop-standard/v1.

PY - 2026/4/1

Y1 - 2026/4/1

N2 - The over-tilting of Dirac cones has led to various fascinating quantum phenomena. In this study, we demonstrate that the distinct geometry of two-dimensional type-II Dirac cones dictates the emergence of anomalous acoustic plasmons (AAPs) that deviate from that of the conventional (Formula presented) (Formula presented) plasmon. The first AAP originates from the strong hybridization of two pockets with large velocity anisotropy at one Dirac point. The second AAP is attributed to the significant enhancement in band correlation around the open Fermi surface. These plasmons exhibit valley-dependent chirality along the tilting direction caused by chiral electron dispersion. Meanwhile, we discuss the tunability of plasmon dispersion and lifetime by tuning the gap and dielectric substrate. Our work provides a promising framework to generate novel plasmons in Dirac materials.

AB - The over-tilting of Dirac cones has led to various fascinating quantum phenomena. In this study, we demonstrate that the distinct geometry of two-dimensional type-II Dirac cones dictates the emergence of anomalous acoustic plasmons (AAPs) that deviate from that of the conventional (Formula presented) (Formula presented) plasmon. The first AAP originates from the strong hybridization of two pockets with large velocity anisotropy at one Dirac point. The second AAP is attributed to the significant enhancement in band correlation around the open Fermi surface. These plasmons exhibit valley-dependent chirality along the tilting direction caused by chiral electron dispersion. Meanwhile, we discuss the tunability of plasmon dispersion and lifetime by tuning the gap and dielectric substrate. Our work provides a promising framework to generate novel plasmons in Dirac materials.

UR - https://www.scopus.com/pages/publications/105037719672

U2 - 10.1088/0256-307X/43/4/040707

DO - 10.1088/0256-307X/43/4/040707

M3 - Letter

AN - SCOPUS:105037719672

SN - 0256-307X

VL - 43

JO - Chinese Physics Letters

JF - Chinese Physics Letters

IS - 4

ER -

Anomalous Acoustic Plasmons in Two-Dimensional Over-Tilted Dirac Bands

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