双层石墨烯中的偶数分母分数量子霍尔态  

Even-denominator fractional quantum Hall state in bilayer graphene

作　　者：李庆鑫 黄焱 陈以威 朱雨剑 朱旺 宋珺威 安冬冬 甘祺康 王开元 王浩林 †麦志洪 Andy Shen 郗传英[3] 张警蕾 于葛亮 王雷 Li Qing-Xin;Huang Yan;Chen Yi-Wei;Zhu Yu-Jian;Zhu Wang;Song Jun-Wei;An Dong-Dong;Gan Qi-Kang;Wang Kai-Yuan;Wang Hao-Lin;Mai Zhi-Hong;Andy Shen;Xi Chuan-Ying;Zhang Jing-Lei;Yu Ge-Liang;Wang Lei(National Laboratory of Solid State Microstructures,Department of Physics,Nanjing University,Nanjing 210093,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China;High Magnetic Field Laboratory,Chinese Academy of Sciences,Hefei 230031,China;Hubei Jiufengshan Laboratory,Wuhan 430206,China)

机构地区：[1]南京大学物理学院,固体微结构物理国家重点实验室,南京210093 [2]南京大学,人工微结构科学与技术协同创新中心,南京210093 [3]中国科学院强磁场科学中心,合肥230031 [4]湖北九峰山实验室,武汉430206

出　　处：《物理学报》2022年第18期73-78,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12074173);江苏省创新人才和企业家项目(批准号:JSSCTD202101);中国科学院合肥科学中心优秀用户项目(批准号:2021HSC-UE007,2021HSC-UE011);江苏省杰出青年基金(批准号:BK20220066)资助的课题。

摘　　要：在半填充的朗道能级,复合费米子手征p波配对的Moore-Read态具有e/4的分数激发,其中部分这种准粒子服从非阿贝尔统计,有望用于实现拓扑量子计算.双层石墨烯由于其电子的SU(4)对称性和电场对其性质的方便调控性,成为研究多分量量子霍尔态的理想平台,是实现非阿贝尔统计的候选者.本文利用干法转移技术制备了双层石墨烯/氮化硼异质结,通过电学输运测量展示了双层石墨烯在调节外电场和磁场下的量子霍尔态行为.在强磁场下,观测到了朗道能级填充因子为–5/2,–1/2,3/2的伴随着量子化霍尔电导的不可压缩态.随着磁场继续增强,这些偶数分母量子霍尔态特征先增强再减弱,对应朗道能级波函数的极化.实验结果暗示观察到的这些偶数分母分数量子霍尔态属于由Pffafian波函数描述的拓扑态.At a half-filled Landau level,composite fermions with chiral p-wave pairing will form a Moore-Read state which hosts charge-e/4 fractional excitation.This excitation supports non-Abelian statistics and has potential to enable topological quantum computation.Owing to the SU(4)symmetry of electron and electric-field tunability,the bilayer graphene becomes an ideal platform for exploring physics of multi-component quantum Hall state and is candidate for realizing non-Abelian statistics.In this work,high-quality bilayer graphene/hBN heterostructure is fabricated by using dry-transfer technique,and electric transport measurement is performed to study quantum Hall state behavior in bilayer graphene under electric field and magnetic field.Under strong magnetic field,the sequences of incompressible state with quantized Hall conductivity are revealed at–5/2,–1/2,3/2 filling of Landau level.The feature of even-denominator quantum Hall state is more visible then weaker with increasing magnetic field,and this corresponds to the polarization of Landau level wave function.The experimental results indicate that the observed even-denominator fractional quantum Hall state belongs to the topological phase described by Pfaffian wavefunction.

关 键 词：石墨烯 分数量子霍尔效应 拓扑相 

分 类 号：TQ127.11[化学工程—无机化工]