PHYSICAL REVIEW B 103, 174418 (2021) Weak Kondo effect in the monocrystalline transition metal dichalcogenide ZrTe 2 Yihao Wang , 1, 2 Changzheng Xie, 3 Junbo Li, 2, 4 Zan Du, 2, 4 Liang Cao, 2 Yuyan Han , 2 Lin Zu, 1 Hongchao Zhang, 5 Huamin Zhu, 5 Xueying Zhang, 1, 5, * Yimin Xiong, 2, 6 , † and Weisheng Zhao 1, 5, ‡ 1 School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China 2 Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, China 3 Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province, School of Physics and Materials Engineering, Hefei Normal University, Hefei 230601, China 4 Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230026, China 5 Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266600, China 6 Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China (Received 15 November 2020; revised 28 April 2021; accepted 3 May 2021; published 17 May 2021) Zr-Te compounds are an ideal platform to investigate novel electrical transport properties. Here we report the Kondo effect in single-crystalline ZrTe 2 . When T < 8 K, ZrTe 2 exhibits a logT dependence of resistivity, which may derive from three different mechanisms, including electron-electron interaction, weak localization, and Kondo effect. By measuring transport properties with magnetic field along different directions, the former two mechanisms were excluded. Isotropic negative magnetoresistance was extracted by subtracting different quadratic background signals caused by Lorentz force, which reveals the existence of a weak Kondo effect in this material. DOI: 10.1103/PhysRevB.103.174418 I. INTRODUCTION Transition-metal dichalcogenides (TMDCs) are attracting renewed research interest because of their rich and tunable physical properties [1]. For example, WTe 2 exhibits an ex- tremely large magnetoresistance (XMR) effect, which has potential applications in data storage [2,3]; the applied pres- sure suppresses charge density waves (CDWs) and induce superconductivity in 1T-TaS 2 [4]. On the other hand, TMDCs are typical layered materials with weak out-of-plane van der Waals interactions, making it possible to reduce the thickness to atomic scale. By stacking two or more atomic layers of different TMDCs, collective quantum phenomena at the in- terfaces are expected to appear [5–7]. These make TMDCs candidates for fabricating novel electronic and spintronic de- vices. TMDCs show various transport behaviors at low tempera- ture. For VTe 2 , the localized magnetic moment derives from interstitial vanadium ions, giving rise to the Kondo effect [8]. Cao et al. reported the weak localization generated by defects in VSe 2 single crystals and laminates [9]. Barua et al. observed the Kondo effect in single-crystalline VSe 2 [10]. The above diverse results indicate that the content of transition metals and defects in TMDCs are crucial for their physical properties. Figuring out the mechanisms behind transport phe- nomena will help deepen understandings about this system. * xueying.zhang@buaa.edu.cn † yxiong@hmfl.ac.cn ‡ weisheng.zhao@buaa.edu.cn The zirconium ditelluride, ZrTe 2 , a member of TMDCs, has recently drawn research interest because of its band topologies. Angle-resolved photoemission spectroscopy (ARPES) measurements on ZrTe 2 film grown on SrTiO 3 substrate give linear dispersions that indicate the existence of massless Dirac fermions [11]. Related transport evidences, including large magnetoresistance and negative magnetoresistance, have also been observed in ZrTe 2 /InAs films [12]. For film/substrate systems, charge transfer at interfaces, strain from substrates, and the modulation of thickness may serve as crucial factors that influence physical properties of the films. According to previous studies, bulk ZrTe 2 is theoretically predicted to be a topological crystalline insulator (TCI) [13,14]. However, transport evidences backing up the existence of a TCI state in ZrTe 2 are still absent. Besides ZrTe 2 , other zirconium telluride compounds also exhibit novel physical properties. ZrTe is theoretically predicted to be a threefold degeneracy topological semimetal [15–17]. Related features including high carrier mobility and light cyclotron effective mass have been observed in ZrTe single crystals [18]. ZrTe 5 has been extensively studied for its resistivity anomaly, unusual thermoelectric properties, and nontrivial band topology [19–23]. In addition, superconductivity could be induced by intercalating copper atoms in ZrTe 2 . Band-structure calculations give a dispersion curve containing a bulk three-dimensional (3D) Dirac-cone-like feature, indicating that Cu x ZrTe 2 is a candidate for topological superconductors [24]. Consequently, Zr-Te compounds are an ideal platform to investigate band topologies in materials. Although extensive studies have been performed on ZrTe 2 film and 2469-9950/2021/103(17)/174418(8) 174418-1 ©2021 American Physical Society