Cross-Correlated Interface Research Unit

Principal Investigator

PI Name Pu Yu
Degree Ph.D.
Title Unit Leader
Brief Resume
2011Ph.D. in Physics, University of California, Berkeley, USA
2012Postdoctoral Researcher, Correlated Electron Research Group, RIKEN, Japan
2012Assistant Professor, Tsinghua University, Beijing, China
2014Unit Leader, Cross-Correlated Interface Research Unit, Cross-Divisional Materials Research Program, RIKEN Center for Emergent Matter Science (-present)
2017Associate Professor, Tsinghua University, Beijing, China (-present)


Our research unit is dedicated to exploring the emergent phenomena at complex oxide and other cross-correlated heterostructures and interfaces. In particular, we are interested about quantum manipulation of ferroelectric and ferromagnetic properties by means of heteroepitaxy, artificial design of novel multiferroic materials with strong magnetoelectric coupling and emergent phenomena (with a strong focus on the spin and charge degrees of freedom) at complex oxide interfaces and their cross correlations to other correlated material systems. Our goal is to reveal the underlying mechanisms of these heretofore-unexplored functionalities, and transfer them into novel device concepts for applications.

Research Fields

Condensed Matter Physics, Materials Sciences


Interface electronic structure
Magnetoelectric effect
Thin films and interfaces


Electric field control of ionic evolution: a novel strategy to redesign materials

Electric-field control of phase transformation with ion transfer is of great interests in materials science with enormous practical applications. We demonstrated a reversible and nonvolatile electric-field control of oxygen and hydrogen ion evolutions within the model system of brownmillerite SrCoO2.5 by ionic liquid gating, which forms solid foundation for conceptually new tri-state magnetoelectric and electrochromic effects. Along this vein, we further demonstrated the protonation induced metal-insulator transition and enhanced superconductivity in WO3 and iron-based superconductors, respectively. Using Co/SrCoO2.5 as model system, we introduced a new strategy to achieve the room temperature electric-field control of magnetism in Co layer accompanied by the bipolar resistance switch. In this case, the electric field controlled oxygen evolution leads to oxygen ion accumulation (gating) at the interface, which modulate the magnetic interaction within the Co surface layer and eventually results in the intriguing magnetoelectric coupling. We envision that these approaches bring in a new tuning knob to manipulate the coupling and correlation between degrees of freedom for the discovery of novel materials with rich functionalities.

Manipulation the coupling and correlation between degrees of freedom through ionic evolution.


Pu Yu

Unit Leader R