Observation of chiral edge states in gapped nanomechanical graphene

被引：51
作者：
Xi, Xiang [1 ]
Ma, Jingwen [1 ]
Wan, Shuai [2 ,3 ]
Dong, Chun-Hua [2 ,3 ]
Sun, Xiankai [1 ]
机构：
[1] Chinese Univ Hong Kong, Dept Elect Engn, Shatin, Hong Kong, Peoples R China
[2] Univ Sci & Technol China, Key Lab Quantum Informat, Hefei 230026, Anhui, Peoples R China
[3] Univ Sci & Technol China, CAS Ctr Excellence Quantum Informat & Quantum Phy, Hefei 230026, Anhui, Peoples R China
来源：
SCIENCE ADVANCES | 2021年 / 7卷 / 02期
基金：
中国国家自然科学基金;
关键词：
PHASE;
D O I：
10.1126/sciadv.abe1398
中图分类号：
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号：
07 ; 0710 ; 09 ;
摘要：
Emerging in diverse areas of physics, edge states have been exploited as an efficient strategy of manipulating electrons, photons, and phonons for next-generation hybrid electro-optomechanical circuits. Among various edge states, gapless chiral edge states harnessing quantum spin/valley Hall effects in graphene or graphene-like materials are especially unique. Here, we report on an experimental demonstration of chiral edge states in gapped "nanomechanical graphene"-a honeycomb lattice of free-standing silicon nitride nanomechanical membranes with broken spatial inversion symmetry. These chiral edge states can emerge from the conventional flat-band edge states by tuning the on-site boundary potentials. We experimentally demonstrated that they are backscattering-immune against sharp bends and exhibit the "valley-momentum locking" effect. We further realized smooth transition between the chiral edge states and the well-known valley kink states. Our results open the door to experimental investigation of exotic graphene-related physics in the very-high-frequency integrated nanomechanical systems.
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页数：7
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