title: Signatures of the Adler-Bell-Jackiw chiral anomaly in a Weyl fermion semimetal.
abstract: Weyl semimetals provide the realization of Weyl fermions in solid-state physics. Among all the physical phenomena that are enabled by Weyl semimetals, the chiral anomaly is the most unusual one. Here, we report signatures of the chiral anomaly in the magneto-transport measurements on the first Weyl semimetal TaAs. We show negative magnetoresistance under parallel electric and magnetic fields, that is, unlike most metals whose resistivity increases under an external magnetic field, we observe that our high mobility TaAs samples become more conductive as a magnetic field is applied along the direction of the current for certain ranges of the field strength. We present systematically detailed data and careful analyses, which allow us to exclude other possible origins of the observed negative magnetoresistance. Our transport data, corroborated by photoemission measurements, first-principles calculations and theoretical analyses, collectively demonstrate signatures of the Weyl fermion chiral anomaly in the magneto-transport of TaAs.
authors.affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
authors.forename: Cheng-Long
authors.initials: CL
authors.lastname: Zhang
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Su-Yang
authors.initials: SY
authors.lastname: Xu
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Ilya
authors.initials: I
authors.lastname: Belopolski
authors.affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
authors.forename: Zhujun
authors.identifier: http://orcid.org/0000-0003-1793-1461
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Ziquan
authors.initials: Z
authors.lastname: Lin
authors.affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Tong
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Guang
authors.initials: G
authors.lastname: Bian
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Nasser
authors.initials: N
authors.lastname: Alidoust
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.|Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Chi-Cheng
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.|Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Shin-Ming
authors.identifier: http://orcid.org/0000-0003-4273-9682
authors.initials: SM
authors.lastname: Huang
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.|Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Tay-Rong
authors.initials: TR
authors.lastname: Chang
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.|Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Guoqing
authors.identifier: http://orcid.org/0000-0003-1180-3127
authors.initials: G
authors.lastname: Chang
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.|Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Chuang-Han
authors.identifier: http://orcid.org/0000-0002-2394-8537
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.|Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Horng-Tay
authors.initials: HT
authors.lastname: Jeng
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.|Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.|Department of Physics, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: Madhab
authors.initials: M
authors.lastname: Neupane
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Sanchez
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Hao
authors.identifier: http://orcid.org/0000-0002-6495-874X
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.|Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Hsin
authors.initials: H
authors.lastname: Lin
authors.affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Physics, South University of Science and Technology of China, Shenzhen, China.
authors.forename: Hai-Zhou
authors.identifier: http://orcid.org/0000-0002-6708-0223
authors.initials: HZ
authors.lastname: Lu
authors.affiliation: Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Shun-Qing
authors.initials: SQ
authors.lastname: Shen
authors.affiliation: Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Titus
authors.identifier: http://orcid.org/0000-0003-0604-041X
authors.initials: T
authors.lastname: Neupert
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: M
authors.identifier: http://orcid.org/0000-0001-9730-3128
authors.initials: M
authors.lastname: Zahid Hasan
authors.affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Jia