Band geometry induced high angular momentum excitonic superfluid in gapped chiral fermion systems

Letter

Band geometry induced high angular momentum excitonic superfluid in gapped chiral fermion systems

Huaiyuan Yang, Yuelin Shao, Yuanfeng Xu, Xi Dai, and Xin-Zheng Li

Phys. Rev. B 109, L201401 – Published 3 May 2024

Abstract

We study the exciton condensation in the heterostructures where the electron layer and the hole layer formed by gapped chiral fermion (GCF) systems are separately gated. High angular momentum such as $p$ - and $d$ -wave-like excitonic pairing may emerge when the gap of the GCF systems is small compared to the Fermi energy, and the chiral winding numbers of the electrons and holes are the same. This is a result of the nontrivial band geometry and can be linked to the Berry curvature when projected onto the Fermi surface. In realistic systems, we propose that staggered graphene and surface states of magnetically doped topological insulators or intrinsic axion insulators are promising candidates for realizing $p$ -wave exciton superfluid, and anomalous Hall conductivity can be used as a signature in experiments.

Received 20 January 2024
Revised 26 March 2024
Accepted 11 April 2024

DOI:https://doi.org/10.1103/PhysRevB.109.L201401

Physics Subject Headings (PhySH)

Excitons Surface states

2-dimensional systems

k dot p method

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Huaiyuan Yang ¹, Yuelin Shao ^2,3,*, Yuanfeng Xu⁴, Xi Dai^5,†, and Xin-Zheng Li ^1,6,7,‡

¹State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Frontier Science Center for Nano-optoelectronics and School of Physics, Peking University, Beijing 100871, People's Republic of China
²Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
³School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
⁴Center for Correlated Matter, School of Physics, Zhejiang University, No. 866, Yuhangtang Road, Xihu District, Hangzhou 310058, Zhejiang Province, People's Republic of China
⁵Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong
⁶Interdisciplinary Institute of Light-Element Quantum Materials, Research Center for Light-Element Advanced Materials, and Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, People's Republic of China
⁷Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, People's Republic of China

^*ylshao@iphy.ac.cn
^†daix@ust.hk
^‡xzli@pku.edu.cn

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Issue

Vol. 109, Iss. 20 — 15 May 2024

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