COMMUNICATION © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim (1 of 5) 1600228 wileyonlinelibrary.com Evidence of Both Surface and Bulk Dirac Bands and Anisotropic Nonsaturating Magnetoresistance in ZrSiS Xuefeng Wang,* Xingchen Pan, Ming Gao, Jihai Yu, Juan Jiang, Junran Zhang, Huakun Zuo, Minhao Zhang, Zhongxia Wei, Wei Niu, Zhengcai Xia, Xiangang Wan, Yulin Chen, Fengqi Song,* Yongbing Xu, Baigeng Wang, Guanghou Wang, and Rong Zhang* Prof. X. F. Wang, M. Gao, J. R. Zhang, M. H. Zhang, W. Niu, Prof. Y. B. Xu, Prof. R. Zhang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures School of Electronic Science and Engineering Nanjing University Nanjing 210093, P. R. China E-mail: xfwang@nju.edu.cn; rzhang@nju.edu.cn X. C. Pan, J. H. Yu, Z. X. Wei, Prof. X. G. Wan, Prof. F. Q. Song, Prof. B. G. Wang, Prof. G. H. Wang School of Physics Nanjing University Nanjing 210093, P. R. China E-mail: songfengqi@nju.edu.cn Dr. J. Jiang, Prof. Y. L. Chen School of Physical Science and Technology ShanghaiTech University CAS-Shanghai Science Research Center Shanghai 200031, P. R. China Dr. H. K. Zuo, Prof. Z. C. Xia Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Wuhan 430074, P. R. China DOI: 10.1002/aelm.201600228 on the Fermi level of WTe 2 , leading to classic MR resonance and an unsaturated MR until a large field of 60 T. [2] In WTe 2 , intriguing linear MR appears when the field is aligned both in the perpendicular and parallel directions. [22–24] When large MR is suppressed by a pressure, superconductivity arises due to possible Fermi level nesting. [25,26] Similar physics generating a large quadratic MR of up to, and in fact over, 10 000 times has been observed at 9 T in TaAs. [27] Recently, the type-II Weyl semi- metal has been studied [28] and confirmed by visiting the empty states using laser pumping. [29] Intense interest paves the way to further investigate the aforementioned topic. ZrSiS, with the iron-pnictide super- conductor LiFeAs structure, has been predicted to be a 2D topological insulator [30] and hosts several bulk Dirac cones. [31] In this Communication, combining the studies of high-field magnetotransport until 53 T, angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) cal- culations, we provide the unambiguous evidence of the ZrSiS as a new type of quantum material with the Dirac cones from both the bulk and surface electronic states. The unconventional MR keeps unsaturated until a intense field of 53 T and depicts the interesting butterfly-shaped angular dependence. Figure 1 shows the transport measurements of the single crystal. The positive temperature-dependent resistance curve indicates the metallic behavior. The nonmagnetic material exhibits a strong MR response, as shown in Figure 1a, where the resistance increases with increasing magnetic field. At the temperature of 2 K and the magnetic field of 9 T, the MR ratio reaches nearly 10 000% (Figure 1a). The Hall resistance is meas- ured in a six-electrode configuration, illustrating a linear trend at high temperatures and a bending feature at temperatures lower than 50 K (see Figure S2 in the Supporting Information). This indicates a dominant transport electronic state at high temperatures and more electronic states participating in the transport at lower temperatures. The MR keeps increasing with the magnetic field and shows no saturation when an intense pulsed field up to 53 T is applied. The MR ratio increases when the temperature decreases and can reach 170 000% at 53 T at 2 K (Figure 1a). The MR unsaturation is shown more explic- itly in the log–log frame, as shown in Figure 1c, where the MR increases steadily from very low to the extreme field of 53 T. Interestingly, when we measure the MR at a series of config- urations with different angles between the field and crystal cleavage plane, it is found that the maximum MR ratio of nearly 200 000% is reached at around 45° (Figure 1b). Figure 1c Recently, mining topological anomalies in electronic structures and transport signature has been a central topic in the commu- nity of quantum materials. [1–8] Some new concepts are emerging including topological insulators, topological Dirac semimetals, and Weyl semimetals, all of which have demonstrated novel transport properties with potential device applications. [1,9–13] Most topological insulators and Weyl/Dirac semimetals are featured with a linear/quasi-linear dispersion in their band structures, which drives modulated electronic accumulation in the lowest Landau level and paves the dominance of linear mag- netoresistance (MR) in high magnetic fields. [7,8,14–17] The large Berry curvature exists in the bands of TaAs and NbP, which casts a large room-temperature MR ratio of up to 100 000. [17,18] It could also be related to the unexpectedly high room-temper- ature mobility of these materials. The opposite Weyl charges can be found in the Weyl/Dirac semimetals, which can simu- late the chiral anomaly of quasiparticle transport proposed in high energy physics. This leads to intense negative MR when the field is aligned along the direction of the current, which vanishes totally if the field is tilted by a very small angle. [18–21] Perfectly compensated electron/hole pockets have been found www.MaterialsViews.com www.advelectronicmat.de Adv. Electron. Mater. 2016, 1600228