Prof. Xuefeng Sun[University of Science and Technology of China]

Title: Thermal Conductivity of Geometric Frustration Materials at Low Temperature

Time:  10:00-11:00, Jan. 18, 2019

Place: Conference room 410, HPSTAR (Shanghai)

Host: Lin Wang

Polycom: 02120004 

Abstract:

Geometric frustration is well known. For example, spin systems with certain geometric structures can not satisfy all competitive interactions at the same time, which makes the system have a large number of degenerate states. When the temperature approaches absolute zero, the combination of quantum fluctuations and geometric frustrations can produce some strange quantum liquids in solids, accompanied by some special element excitations. Low temperature thermal conductivity is a basic physical property of solid materials and an effective means to characterize the excitation of low energy elements. Several kinds of geometric frustration materials, including quantum spin liquid Tb2Ti2O7 and quantum electric dipole liquid BaFe12O19, were characterized and discussed by means of low temperature heat conduction measurements.

Biography of the Speaker:

Xuefeng Sun

Professor of Physics

College of Physics

University of Science and Technology of China, Hefei, Anhui 230026 China 

Email: xfsun@ustc.edu.cn                     

Education

1989 – 1993   Anhui University, Physics, Bachelor 

1993 – 1998   University of Science and Technology of China, Ph.D.

Working Experience

1998 – 2000   University of Science and Technology of China, Physics Dept., Lecturer

2000 – 2002   University of Science and Technology of China, Physics Dept., Ass. Prof.

2000 – 2002   STA Fellow, Japan

2002 – 2006   Researcher, Japan

2006 – present   University of Science and Technology of China , Professor

Research Interests

1) Low dimensional magnetic materials;

2) High Tc superconductivity;

3) Strong correlated systems.

Selected Publications

1) Field-Driven Quantum Criticality in the Spinel Magnet ZnCr2Se4 - Phys. Rev. Lett. - 2018/4 - 120, 147204

2) Quantum electric-dipole liquid on a triangular lattice - Nature Commun. - 2016 - 7, 10569

3) Low-Temperature Low-Field Phases of the Pyrochlore Quantum Magnet Tb2Ti2O7 - Phys. Rev. Lett. - 2013 - 110, 137201

4) Low-Temperature Heat Transport in the Low-Dimensional Quantum Magnet NiCl_2-4SC(NH_2)_2 - Phys. Rev. Lett. - 2009 - 102, 167202

5) Electronic Inhomogeneity and Breakdown of the Universal Thermal Conductivity in Cuprate Superconductors - Phys. Rev. Lett. - 2006 - 96, 017008 

6) Metal-to-Insulator Crossover in YBa2Cu3Oy Probed by Low-Temperature Quasiparticle Heat Transport - Phys. Rev. Lett. - 2004 - 93, 107001 

7) Thermal Conductivity of Pr1.3-xLa0.7CexCuO4 Single Crystals and Signatures of Stripes in an Electron-doped Cuprate - Phys. Rev. Lett. - 2004 - 92, 047001 

8) Magnetic-Field-Induced Localization of Quasiparticles in Underdoped La2-xSrxCuO4 Single Crystals - Phys. Rev. Lett. - 2003 - 90, 117004