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Theoretical Modeling Of Various Spectroscopies For Cuprates And Topological Insulators, Susmita Basak
Theoretical Modeling Of Various Spectroscopies For Cuprates And Topological Insulators, Susmita Basak
Susmita Basak
Spectroscopies resolved highly in momentum, energy and/or spatial dimensions are playing an important role in unraveling key properties of wide classes of novel materials. However, spectroscopies do not usually provide a direct map of the underlying electronic spectrum, but act as a complex `filter' to produce a `mapping' of the underlying energy levels, Fermi surfaces (FSs) and excitation spectra. The connection between the electronic spectrum and the measured spectra is described as a generalized `matrix element effect'. The nature of the matrix element involved differs greatly between different spectroscopies. For example, in angle-resolved photoemission (ARPES) an incoming photon knocks out …
Spin Texture On The Warped Dirac-Cone Surface States In Topological Insulators, Susmita Basak, Hsin Lin, L. A. Wray, S. Y. Xu, L. Fu, M. Z. Hasan, A. Bansil
Spin Texture On The Warped Dirac-Cone Surface States In Topological Insulators, Susmita Basak, Hsin Lin, L. A. Wray, S. Y. Xu, L. Fu, M. Z. Hasan, A. Bansil
Susmita Basak
We have investigated the nature of surface states in the Bi₂Te₃ family of three-dimensional topological insulators using first-principles calculations as well as a model Hamiltonian approach. When the surface Dirac cone is warped due to Dresselhaus spin-orbit coupling in rhombohedral structures, the spin acquires a finite out-of-the-plane component. We provide a simple, minimal model to describe the in-plane spin texture of the warped surface Dirac cone observed in experiments where spins are seen to be not aligned perpendicular to the electron momentum. Our k·p model calculation reveals that this in-plane spin texture requires fifth-order Dresselhaus spin-orbit coupling terms