Prediction of two-dimensional electron gas mediated magnetoelectric coupling at ferroelectric PbTiO_3/SrTiO_3 heterostructures

摘要

First-principles calculations predict the emergence of magnetoelectric coupling mediated by two-dimensional electron gas (2DEG) at the ferroelectric PbTiO_3/SrTiO_3 heterostructure. Free electrons endowed by naturally existing oxygen vacancies in SrTiO_3 are driven to the heterostructure interface under the polarizing field of ferroelectric PbTiO_3 to form a 2DEG. The electrons are captured by interfacial Ti atoms, which surprisingly exhibits ferromagnetism even at room temperature with a small critical density of ～15.5 μC/cm~2. The ferroelectricity-controlled ferromagnetism mediated by interfacial 2DEG shows strong magnetoelectric coupling strength, enabling convenient control of magnetism by electric field and vice versa. The PbTiO_3/SrTiO_3 heterostructure is cheap, easily grown, and controllable, promising future applications in low-cost spintronics and information storage at ambient condition.