Abstract
We study Coulomb drag between the top and bottom surfaces of topological insulator films. We derive a kinetic equation for the thin-film spin density matrix containing the full spin structure of the two-layer system, and analyze the electron-electron interaction in detail in order to recover all terms responsible for Coulomb drag. Focusing on typical topological insulator systems, with a film thicknesses d up to 6 nm, we obtain numerical and approximate analytical results for the drag resistivity ρD and find that ρD is proportional to T2d-4na-3/2np-3/2 at low temperature T and low electron density na,p, with a denoting the active layer and p the passive layer. In addition, we compare ρD with graphene, identifying qualitative and quantitative differences, and we discuss the multi-valley case, ultra thin films and electron-hole layers.
Original language | English |
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Pages (from-to) | 72-79 |
Number of pages | 8 |
Journal | Physica E: Low-Dimensional Systems and Nanostructures |
Volume | 79 |
DOIs | |
Publication status | Published - 1 May 2016 |
Externally published | Yes |
Keywords
- Coulomb drag
- Electron-electron interactions
- Topological insulator