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- Type of Document: Ph.D. Dissertation
- Language: Farsi
- Document No: 50164 (04)
- University: Sharif University of Technology
- Department: Physics
- Advisor(s): Jafari, Akbar
- Abstract:
- We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM).We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect. Also, We find that singlet superconducting pairing can lead to Majorana fermions in three dimensional Dirac superconductors (3DDS) if the pairing order parameter is a pseudo-scalar, i.e. it changes sign under mirror reflection. The pseudo-scalar superconducting order parameter, Δ5 can close and reopen the spectral gap caused by the scalar Dirac mass ΔD in a 3DDM, giving rise to a two-dimensional Majorana sea (2DMS) at the plane of the gap kink. By bringing the Hamiltonian into a canonical form which then gives the winding number, we show that this system belongs to the DIII class of topological superconductors. We calculate the transport signature of 2DMS, namely a perfect Andreev-Klein transmission that manifests in a robust peak in the differential conductance. Further, we find the 4 periodicity in the Δ5jΔDjΔ5 Josephson junctions
- Keywords:
- Quantum Transport ; Superconductor ; Topology ; Topological Superconductor ; Phase Transition ; Bismuth ; Three Dimensional Dirac Materials
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محتواي کتاب
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- فهرست تصاویر
- معرفی پژوهش
- مواد دیراکی در فیزیک ماده چگال
- ترابرد کوانتومی در اتصالات ضعیف
- مقدمه
- نظریه پراکندگی و فرمول لاندائر
- ترابرد کوانتومی در اتصالهای شامل ابررسانا
- توپولوژی
- قضیه جکیو-ربای و حالتهای مرزی انرژی-صفر
- فازی بری و ناوردای چرن
- اثر کوانتومی هال صحیح
- مدل زنجیره کیتایف
- مدل هالدین
- اثر کوانتومی اسپینی هال
- عایق توپولوژیک دو بعدی و ناوردای Z2
- عایقهای توپولوژیک سه بعدی
- ابررساناهای توپولوژیک
- طبقهبندی فازهای توپولوژی بر مبنای خواص تقارنی گسسته
- فازهای توپولوژیک با تقارن محافظت شدهSymmetry Protected Topological Phase (SPT phase)
- جمعبندی
- ترابرد کوانتومی در مواد دیراک سه بعدی
- ترابرد کوانتومی در ابررسانای دیراک سه بعدی
- پیوستها
- مراجع
- نمایه