Assistant Professor of Physics
Ph.D., Stanford University
B.S., Fudan University
Areas of Research
I am interested in understanding the microscopic behaviors of electrons in solids beyond the description by solid state physics textbooks. These behaviors are generally very complex and featured by a rich interplay among multiple degrees of freedom, charge, lattice, spin and orbital. To disentangle their individual contributions and decipher the microscopic mechanism of their interactions, I mainly use three kinds of techniques using soft x-rays to study the materials in, respectively, the real, momentum and reciprocal spaces and to obtain detailed insights that are otherwise unattainable but required for forging a global understanding of the complex problem.
In short, our group has been performing experimental studies of correlated electron systems (high-temperature cuprate superconductors and other complex oxides) in forms of bulk single crystals and thin films with various techniques based on synchrotron radiations, mainly, angle-resolved photoemission spectroscopy, resonant soft x-ray scattering, scanning transmission x-ray microscopy, etc..
P. D. C. King, R. H. He, T. Eknapakul, S.-K. Mo, Y. Kaneko, S. Harashima, Y. Hikita, S. Bahramy, C. Bell, Y. Tokura, Z.-X. Shen, H. Y. Hwang, F. Baumberger and W. Meevasana, “Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO3”, Phys. Rev. Lett. 108, 117602 (2012).
R.-H. He, M. Fujita, M. Enoki, M. Hashimoto, S. Iikubo, S.-K. Mo, H. Yao, T. Adachi, Y. Koike, Z. Hussain, Z.-X. Shen, K. Yamada, “Hidden itinerant-spin phase in heavily overdoped La2-xSrxCuO4 superconductors revealed by dilute Fe doping: A combined neutron scattering and angle-resolved photoemission study”, Phys. Rev. Lett. 107, 127002 (2011).
M. Hashimoto, R.-H. He, J. P. Testaud, W. Meevasana, R. G. Moore, D. H. Lu, Y. Yoshida, H. Eisaki, T. P. Devereaux, Z. Hussain, Z.-X. Shen, “Reaffirming the dx2-y2 superconducting gap using the autocorrelation angle-resolved photoemission spectroscopy of Bi1.5Pb0.55Sr1.6La0.4CuO6+d”, Phys. Rev. Lett. 106, 167003 (2011).
R.-H. He*, M. Hashimoto*, H. Karapetyan, J. D. Koralek, J. P. Hinton, J. P. Testaud, V. Nathan, Y. Yoshida, H. Yao, K. Tanaka, W. Meevasana, R. G. Moore, D. H. Lu, S.-K. Mo, M. Ishikado, H. Eisaki, Z. Hussain, T. P. Devereaux, S. A. Kivelson, J. Orenstein, A. Kapitulnik, Z.-X. Shen, “From a single-band metal to a high-temperature superconductor via two thermal phase transitions”, Science 331, 1579-1583 (2011).
R.-H. He, X. J. Zhou, M. Hashimoto, T. Yoshida, K. Tanaka, S.-K. Mo, T. Sasagawa, N. Mannella, W. Meevasana, H. Yao, M. Fujita, T. Adachi, S. Komiya, S. Uchida, Y. Ando, F. Zhou, Z. X. Zhao, A. Fujimori, Y. Koike, K. Yamada, Z. Hussain and Z.-X. Shen, “Doping dependence of the (pi, pi) shadow band in La-based cuprates studied by angle-resolved photoemission spectroscopy”, New J. Phys. 13, 013031 (2011).
W. Meevasana*, P. D. C. King*, R. H. He, S.-K. Mo, M. Hashimoto, F. Baumberger and Z.-X. Shen, “Creation and control of a two-dimensional electron liquid at the bare SrTiO3 surface”, Nature Mat. 10, 114-118 (2011).
M. Hashimoto*, R.-H. He*, K. Tanaka, J. P. Testaud, W. Meevasana, R. G. Moore, D. H. Lu, H. Yao, Y. Yoshida, H. Eisaki, T. P. Devereaux, Z. Hussain and Z.-X. Shen, “Particle-hole symmetry breaking in the pseudogap state of Bi2201”, Nature Phys. 6, 414-418 (2010).
R.-H. He, K. Tanaka, S.-K. Mo, T. Sasagawa, M. Fujita, T. Adachi, N. Mannella, K. Yamada, Y. Koike, Z. Hussain and Z.-X. Shen, “Energy gaps in the failed high-Tc superconductor La1.875Ba0.125CuO4”, Nature Phys. 5, 119-123 (2009).
R. H. He, D. L. Feng, H. Eisaki, J.-i. Shimoyama, K. Kishio and G. D. Gu, “Superconducting order parameter in heavily overdoped Bi2Sr2CaCu2O8+d: A global quantitative analysis”, Phys. Rev. B 69, R220502 (2004) (rapid comm.).