Thermal screening at finite chemical potential on a topological surface and its interplay with proximity-induced ferromagnetism

Abstract

Motivated by recent experiments on EuS/Bi${}_2$Se${}_3$ heterostructures, we study the temperature dependent screening effects on the surface of a three-dimensional topological insulator proximate to a ferromagnetically ordered system. In general, we find that besides the chemical potential and temperature, the screening energy scale also depends on the proximity-induced electronic gap in an essential way. In particular, at zero temperature the screening energy vanishes if the chemical potential is smaller than the proximity-induced electronic gap. We show that at finite temperature, $T$, and/or chemical potential, $\mu$, the Chern-Simons (topological) mass, which is generated by quantum fluctuations arising from the proximity-effect, can be calculated analytically in the insulating regime. In this case the topological mass yields the Hall conductivity associated to edge states. We show that when the chemical potential is inside the gap the topological mass remains nearly quantized at finite temperature.

5 pages, 1 figure; v3: extended version; improved discussion of the Hall conductivity at finite temperature

References in corpus (8)

• Topological Field Theory of Time-Reversal Invariant Insulators
• Interactions and phase transitions on graphene's honeycomb lattice
• The development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3
• Quantum critical point in graphene approached in the limit of infinitely strong Coulomb interaction
• Emerging Weak Localization Effects on Topological Insulator-Insulating Ferromagnet (Bi_2Se_3-EuS) Interface
• Magnetic proximity effect in the 3D topological insulator/ferromagnetic insulator heterostructure
• Fluctuation-induced magnetization dynamics and criticality at the interface of a topological insulator with a magnetically ordered layer
• Strong correlations at topological insulator surfaces and the breakdown of the bulk-boundary correspondence

Cited by in corpus (5)

• Magnetic Proximity Effect and Interlayer Exchange Coupling of Ferromagnetic/Topological Insulator/Ferromagnetic Trilayer
• Dirac electrons and domain walls: a realization in junctions of ferromagnets and topological insulators
• Temperature and Chemical Potential Dependence of the Parity Anomaly in Quantum Anomalous Hall Insulators
• Finite temperature fluctuation-induced order and responses in magnetic topological insulators
• First and second-order metal-insulator phase transitions and topological aspects of a Hubbard-Rashba system