Now showing items 1-20 of 62

    • Anisotropic neutron spin resonance in underdoped superconducting NaFe1−xCoxAs 

      Zhang, Chenglin; Song, Yu; Regnault, L.-P.; Su, Yixi; Enderle, M.; Kulda, J.; Tan, Guotai; Sims, Zachary C.; Egami, Takeshi; Si, Qimiao; Dai, Pengcheng (2014)
      We use polarized inelastic neutron scattering (INS) to study spin excitations in superconducting NaFe0.985Co0.015As (C15) with static antiferromagnetic (AF) order along the a axis of the orthorhombic structure and ...
    • Anomalous Metamagnetism in the Low Carrier Density Kondo Lattice YbRh3Si7 

      Rai, Binod K.; Chikara, S.; Ding, Xiaxin; Oswald, Iain W.H.; Schönemann, R.; Loganathan, V.; Hallas, A.M.; Cao, H.B.; Stavinoha, Macy; Chen, T.; Man, Haoran; Carr, Scott; Singleton, John; Zapf, Vivien; Benavides, Katherine A.; Chan, Julia Y.; Zhang, Q.R.; Rhodes, D.; Chiu, Y.C.; Balicas, Luis; Aczel, A.A.; Huang, Q.; Lynn, Jeffrey W.; Gaudet, J.; Sokolov, D.A.; Walker, H.C.; Adroja, D.T.; Dai, Pengcheng; Nevidomskyy, Andriy H.; Huang, C.-L.; Morosan, E. (2018)
      We report complex metamagnetic transitions in single crystals of the new low carrier Kondo antiferromagnet YbRh3Si7. Electrical transport, magnetization, and specific heat measurements reveal antiferromagnetic order at ...
    • Antiferromagnetic order and spin dynamics in iron-based superconductors 

      Dai, Pengcheng (2015)
      High-transition temperature (high-Tc) superconductivity in the iron pnictides or chalcogenides emerges from the suppression of the static antiferromagnetic order in their parent compounds, similar to copper oxide ...
    • c-axis pressure-induced antiferromagnetic order in optimally P-doped BaFe2(As0.70P0.30)2 superconductor 

      Hu, Ding; Wang, Weiyi; Zhang, Wenliang; Wei, Yuan; Gong, Dongliang; Tam, David W.; Zhou, Panpan; Li, Yu; Tan, Guotai; Song, Yu; Georgii, Robert; Pedersen, Björn; Cao, Huibo; Tian, Wei; Roessli, Bertrand; Yin, Zhiping; Dai, Pengcheng (2018)
      Superconductivity in BaFe2(As1−xPx)2 iron pnictides emerges when its in-plane two-dimensional (2D) orthorhombic lattice distortion associated with nematic phase at Ts and three-dimensional (3D) collinear antiferromagnetic ...
    • Chemical tuning of electrical transport in Ti1−xPtxSe2−y 

      Chen, Justin S.; Wang, Jiakui K.; Carr, Scott V.; Vogel, Sven C.; Gourdon, Olivier; Dai, Pengcheng; Morosan, E. (2015)
      The structural and transport properties of polycrystalline Ti1−xPtxSe2−y(x≤0.13,y≤0.2) are studied, revealing highly tunable electrical properties, spanning nearly ten orders of magnitude in scaled resistivity. Using x-ray ...
    • Correlation-driven metal-insulator transition in proximity to an iron-based superconductor 

      Charnukha, A.; Yin, Z.P.; Song, Y.; Cao, C.D.; Dai, Pengcheng; Haule, K.; Kotliar, G.; Basov, D.N. (2017)
      We report the direct spectroscopic observation of a metal to correlated-insulator transition in the family of iron-based superconducting materials. By means of optical spectroscopy we demonstrate that the excitation spectrum ...
    • Critical quadrupole fluctuations and collective modes in iron pnictide superconductors 

      Thorsmølle, V.K.; Khodas, M.; Yin, Z.P.; Zhang, Chenglin; Carr, S.V.; Dai, Pengcheng; Blumberg, G. (2016)
      The multiband nature of iron pnictides gives rise to a rich temperature-doping phase diagram of competing orders and a plethora of collective phenomena. At low dopings, the tetragonal-to-orthorhombic structural transition ...
    • Direct observation of magnon-phonon coupling in yttrium iron garnet 

      Man, Haoran; Shi, Zhong; Xu, Guangyong; Xu, Yadong; Chen, Xi; Sullivan, Sean; Zhou, Jianshi; Xia, Ke; Shi, Jing; Dai, Pengcheng (2017)
      The magnetic insulator yttrium iron garnet (YIG) with a ferrimagnetic transition temperature of ∼ 560 K has been widely used in microwave and spintronic devices. Anomalous features in spin Seeback effect (SSE) voltages ...
    • Direct observation of spin excitation anisotropy in the paramagnetic orthorhombic state of BaFe2−xNixAs2 

      Man, Haoran; Zhang, Rui; Park, J.T.; Lu, Xingye; Kulda, J.; Ivanov, A.; Dai, Pengcheng (2018)
      We use transport and inelastic neutron-scattering measurements to investigate single crystals of iron pnictide BaFe2−xNixAs2(x=0,0.03), which exhibit a tetragonal-to-orthorhombic structural transition at Ts and stripe ...
    • Doping effects of Cr on the physical properties of BaFe1.9−xNi0.1CrxAs2 

      Gong, Dongliang; Xie, Tao; Zhang, Rui; Birk, Jonas; Niedermayer, Christof; Han, Fei; Lapidus, S.H.; Dai, Pengcheng; Li, Shiliang; Luo, Huiqian (2018)
      We present a systematic study on the heavily Cr doped iron pnictides BaFe1.9−xNi0.1CrxAs2 by using elastic neutron scattering, high-resolution synchrotron x-ray diffraction (XRD), resistivity, and Hall transport measurements. ...
    • Doping evolution of antiferromagnetism and transport properties in nonsuperconducting BaFe2−2xNixCrxAs2 

      Zhang, Rui; Gong, Dongliang; Lu, Xingye; Li, Shiliang; Laver, Mark; Niedermayer, Christof; Danilkin, Sergey; Deng, Guochu; Dai, Pengcheng; Luo, Huiqian (2015)
      We report elastic neutron scattering and transport measurements on the Ni and Cr equivalently doped iron pnictide BaFe2−2xNixCrxAs2. Compared with the electron-doped BaFe2−xNixAs2, the long-range antiferromagnetic (AF) ...
    • Doping evolution of antiferromagnetism and transport properties in nonsuperconducting BaFe2−2xNixCrxAs2 

      Zhang, Rui; Gong, Dongliang; Lu, Xingye; Li, Shiliang; Laver, Mark; Niedermayer, Christof; Danilkin, Sergey; Deng, Guochu; Dai, Pengcheng; Luo, Huiqian (2015)
      We report elastic neutron scattering and transport measurements on the Ni and Cr equivalently doped iron pnictide BaFe2−2xNixCrxAs2. Compared with the electron-doped BaFe2−xNixAs2, the long-range antiferromagnetic (AF) ...
    • Dynamic Spin-Lattice Coupling and Nematic Fluctuations in NaFeAs 

      Li, Yu; Yamani, Zahra; Song, Yu; Wang, Weiyi; Zhang, Chenglin; Tam, David W.; Chen, Tong; Hu, Ding; Xu, Zhuang; Chi, Songxue; Xia, Ke; Zhang, Li; Cui, Shifeng; Guo, Wenan; Fang, Ziming; Liu, Yi; Dai, Pengcheng (2018)
    • Effect of Nematic Order on the Low-Energy Spin Fluctuations in Detwinned BaFe1.935Ni0.065As2 

      Zhang, Wenliang; Park, J.T.; Lu, Xingye; Wei, Yuan; Ma, Xiaoyan; Hao, Lijie; Dai, Pengcheng; Meng, Zi Yang; Yang, Yi-feng; Luo, Huiqian; Li, Shiliang (2016)
      The origin of nematic order remains one of the major debates in iron-based superconductors. In theories based on spin nematicity, one major prediction is that the spin-spin correlation length at (0,π) should decrease with ...
    • Effect of Pnictogen Height on Spin Waves in Iron Pnictides 

      Zhang, Chenglin; Harriger, Leland W.; Yin, Zhiping; Lv, Weicheng; Wang, Miaoyin; Tan, Guotai; Song, Yu; Abernathy, D.L.; Tian, Wei; Egami, Takeshi; Haule, Kristjan; Kotliar, Gabriel; Dai, Pengcheng (2014)
      We use inelastic neutron scattering to study spin waves in the antiferromagnetic ordered phase of iron pnictide NaFeAs throughout the Brillouin zone. Comparing with the well-studied AFe2As2 (A=Ca, Sr, Ba) family, spin waves ...
    • Electron doping evolution of structural and antiferromagnetic phase transitions in NaFe1−xCoxAs iron pnictides 

      Tan, Guotai; Song, Yu; Zhang, Chenglin; Lin, Lifang; Xu, Zhuang; Hou, Tingting; Tian, Wei; Cao, Huibo; Li, Shiliang; Feng, Shiping; Dai, Pengcheng (2016)
      We use transport and neutron diffraction to study the electronic phase diagram of NaFe1−xCoxAs. In the undoped state, NaFeAs exhibits a tetragonal-to-orthorhombic structural transition below Tsfollowed by a collinear ...
    • Electron doping evolution of the magnetic excitations in NaFe1−xCoxAs 

      Carr, Scott V.; Zhang, Chenglin; Song, Yu; Tan, Guotai; Li, Yu; Abernathy, D.L.; Stone, M.B.; Granroth, G.E.; Perring, T.G.; Dai, Pengcheng (2016)
      We use time-of-flight (TOF) inelastic-neutron-scattering (INS) spectroscopy to investigate the doping dependence of magnetic excitations across the phase diagram of NaFe 1 − x Co x As with x = 0 , 0.0175, ...
    • Electron doping evolution of the neutron spin resonance in NaFe1−xCoxAs 

      Zhang, Chenglin; Lv, Weicheng; Tan, Guotai; Song, Yu; Carr, Scott V.; Chi, Songxue; Matsuda, M.; Christianson, A.D.; Fernandez-Baca, J.A.; Harriger, L.W.; Dai, Pengcheng (2016)
      Neutron spin resonance, a collective magnetic excitation coupled to superconductivity, is one of the most prominent features shared by a broad family of unconventional superconductors including copper oxides, iron pnictides, ...
    • Electronic nematic correlations in the stress-free tetragonal state of BaFe2−xNixAs2 

      Man, Haoran; Lu, Xingye; Chen, Justin S.; Zhang, Rui; Zhang, Wenliang; Luo, Huiqian; Kulda, J.; Ivanov, A.; Keller, T.; Morosan, Emilia; Si, Qimiao; Dai, Pengcheng (2015)
      We use transport and neutron scattering to study electronic, structural, and magnetic properties of the electron-doped BaFe2−xNixAs2 iron pnictides in uniaxial-strained and external-stress-free detwinned states. Using a ...
    • Electronic specific heat in BaFe2−xNixAs2 

      Gong, Dongliang; Xie, Tao; Lu, Xingye; Ren, Cong; Shan, Lei; Zhang, Rui; Dai, Pengcheng; Yang, Yi-feng; Luo, Huiqian; Li, Shiliang (2016)
      We have systematically studied the low-temperature specific heat of the BaFe2−xNixAs2 single crystals covering the whole superconducting dome. Using the nonsuperconducting heavily overdoped x=0.3 sample as a reference for ...