Members

Members Profile

Guo-qing Zheng

Guo-qing Zheng

Professor, Department of Physics, Okayama University

Field of Specialty:
Experiment of low temperature condensed matter physics
Specific Topics:
(under construction)

E-mail : zheng[at]psun.phys.okayama-u.ac.jp

RESEARCH

We have investigated the topological superconducting state in systems with broken spatial inversion symmetry as well as doped topological insulators.

In addition to doped topological insulators (Cu,Sr,Nb)xBi2Se3 (Fig.1), we will explore various topological quantum phenomena in compounds containing 3d, 4d and 5d transition metal elements and with strong electron correlations, by combining nuclear magnetic resonance (NMR) and materials synthesis techniques. In particular, we will explore the topological superconducting states in the Cr-based compound R2Cr3As3 (Tc=4.8K) and Pt-based locally non-centrosymmetric SrPtAs. In the former, we have found strong ferromagnetic fluctuations and a superconducting gap with point-nodes, which suggests that this material may be a solid analogue of superfluid 3He. On the other hand, SrPtAs shares many similarities with doped graphene in the electronic band structure and the hexagonal crystal structure. In fact, a d+id superconducting state has been proposed theoretically. We will study these compounds in detail by NMR in single crystals.

Fig.1:NMR result showing a broken spin-rotation symmetry in the superconducting state of CuxBi2Se3(DOI: 10.1038/NPHYS3781)

図2Fig. 2: Crystal structure of Rb2Cr3As3

EDUCATION

1990
Ph.D in Material Physics (Osaka University, Graduate School of Engineering Science)

PROFESSIONAL EXPERIENCE

1990-2004
Assistant Professor, Associate Professor, Osaka University
2004-Present
Professor of Physics, Okayama University

SELECTION OF PUBLICATIONS

"Spin-rotation symmetry breaking in the superconducting state of CuxBi2Se3"
K. Matano, M. Kriener, K. Segawa, Y. Ando, G.-q. Zheng,
Nature Physics 12, 3781-1-4 (May. 2016).
DOI: 10.1038/nphys3781

"Ferromagnetic spin fluctuation and unconventional superconductivity in Rb2Cr3As3 revealed by 75As NMR and NQR."
J. Yang, Z.T. Tang, G.H. Cao and G.-q. Zheng,
Phys. Rev. Lett. 115, 147002-1-5 (Sep. 2015).
DOI: 10.1103/PhysRevLett.115.147002

"Spin-singlet superconductivity with a full gap in locally noncentrosymmetric SrPtAs"
K. Matano, K. Arima, S. Maeda, Y. Nishikubo, K. Kudo, M. Nohara, and G.-q. Zheng,
Phys. Rev. B 89, 140504(R)-1-4 (Apr. 2014).
DOI: 10.1103/PhysRevB.89.140504

"NMR and NQR Studies on Non-centrosymmetric Superconductors Re7B3, LaBiPt, and BiPd."
K. Matano, S. Maeda, H. Sawaoka, Y. Muro, T. Takabatake, B. Joshi, S. Ramakrishnan, K. Kawashima, J. Akimitsu, and G.-q. Zheng,
J. Phys. Soc. Jpn. 82, 084711-1-5 (Jul. 2013) (5 pages).
DOI: http://dx.doi.org/10.7566/JPSJ.82.084711

"Abrupt enhancement of noncentrosymmetry and appearance of a spin-triplet superconducting state in Li2(Pd1-xPtx)3B beyond x=0.8"
S. Harada, J. J. Zhou, Y. G. Yao, Y. Inada, and G.-q. Zheng,
Physical Review B 86, 220502(R)-1-5 (Nov. 2012).
DOI: 10.1103/PhysRevB.86.180501

"Superconducting state in the noncentrosymmetric Mg9.3Ir19B16.7 and Mg10.5Ir19B17.1 revealed by NMR"
K. Tahara, Z. Li, H. X. Yang, J. L. Luo, S. Kawasaki, and G.-q. Zheng,
Physical Review B 80, 060503(R)-1-4 (Aug. 2009).
DOI: 10.1103/PhysRevB.80.060503

"Spin-singlet superconductivity with multiple gaps in PrO0.89F0.11FeAs "
K. Matano, Z.A. Ren, X.L. Dong, L.L. Sun, Z.X. Zhao and G.-q. Zheng,
Europhys. Lett. 83, 57001-1-5 (Sep. 2008).
DOI: 10.1209/0295-5075/83/57001

"Spin Triplet Superconducting State due to Broken Inversion Symmetry in Li2Pt3B"
M. Nishiyama, Y. Inada, and G.-q. Zheng,
Phys. Rev. Lett. 98, 047002-1-4 (Jan. 2007).
DOI: 10.1103/PhysRevLett.98.047002

"Field-Induced Ferromagnetic Order and Colossal magnetoresistance in La1.2Sr1.8Mn2O7:A 139La NMR Study"
Y. Shiotani, J.L. Sarrao, and G.-q. Zheng,
Phys. Rev. Lett. 96, 057203-1-4 (Feb. 2006).
DOI: 10.1103/PhysRevLett.96.057203

"Spin singlet pairing in the superconducting state of NaxCoO2·1.3H2O: Evidence from a 59Co Knight shift in a single crystal"
G.-q. Zheng, K. Matano, D. P. Chen, and C. T. Lin,
Physical Review B 73, 180503(R)-1-4 (May. 2006).
DOI: 10.1103/PhysRevB.73.180503

"Critical point and the nature of the pseudogap of single-layered copper-oxide
Bi2Sr2-xLaxCuO6 superconductors"
G.-q. Zheng, P.L. Kuhns, A.P. Reyes, B. Liang and C.T. Lin,
Phys. Rev. Lett. 94, 047006-1-4 (Feb. 2005).
DOI: 10.1103/PhysRevLett.94.047006

"Unconventional Superconductivity and Electron Correlations in the Cobalt
Oxyhydrate Na0.35CoO2·yH2O from Nuclear Quadrupole Resonance"
T. Fujimoto, G.-q. Zheng,Y. Kitaoka, R. L. Meng, J. Cmaidalka, and C.W. Chu,
Phys. Rev. Lett. 92, 047004-1-4 (Jan. 2004).
DOI: 10.1103/PhysRevLett.92.047004

"Fermi-Liquid Ground State in the n-Type Pr0.91LaCe0.09CuO4 Copper-Oxide Superconductor"
G.-q. Zheng, T. Sato, Y. Kitaoka, M. Fujita and K. Yamada,
Phys. Rev. Lett. 90, 197005-1-4 (May. 2003).
DOI: 10.1103/PhysRevLett.90.197005

"Gapless Magnetic and Quasi-particles Excitations due to the Coexistence of Antiferromagnetism and Superconductivity in CeRhIn5 : 115In-NQR Study under Pressure"
S. Kawasaki, T. Mito, Y. Kawasaki, G.-q. Zheng, Y. Kitaoka, D Aoki, Y Haga,
and Y. Onuki,
Phys. Rev. Lett. 91, 137001-1-4 (Sep. 2003).
DOI: 10.1103/PhysRevLett.91.137001

"Unique spin dynamics and unconventional superconductivity in the layered heavy fermion compound CeIrIn5: NQR evidence"
G.-q. Zheng, K. Tanabe, Ts. Mito, S. Kawasaki, Y. Kitaoka, D. Aoki, Y. Haga, and Y. Onuki,
Phys. Rev. Lett. 86, 4664-1-4 (May. 2001).
DOI: 10.1103/PhysRevLett.86.4664