Charge-Spin Conversion and Electronic Transport in Two-Dimensional Materials and van der Waals Heterostructures
Doctoral thesis, 2022
Interestingly, magnetic memory devices have been demonstrated on an industrial scale; however, the moderate efficiency and fundamental limitations of the conventional materials employed limit their use in consumer electronics. This thesis addresses some of these critical challenges and presents charge-spin conversion mechanisms in layered high SOC materials such as topological insulators, semimetals, and two-dimensional (2D) materials heterostructures. At the same time, this thesis contributes in the direction of integrating memory and logic devices by investigating 2D semiconductor devices with sub-20 nm narrow channel width and memristive switching in field-effect transistors using 2D semiconductors with graphene contacts. Such 2D semiconductors have enormous prospects for next-generation high-performance and energy-efficient nanoscale field-effect transistors and integration with memory technologies. These studies of charge and spin transport in 2D materials and heterostructures can open the door for nanometer-scale memory, logic and sensing technologies.
Spin-orbit coupling
Nanoribbons
Nanotransistor
Graphene
Chemical vapor deposition
Spintronics
Charge-spin conversion
Two-dimensional materials
Proximity effect
van der Waals heterostructure
Author
Anamul Md Hoque
2D-Tech
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Gate-tunable spin-galvanic effect in graphene-topological insulator van der Waals heterostructures at room temperature
Nature Communications,;Vol. 11(2020)
Journal article
Charge-spin conversion in layered semimetal TaTe2 and spin injection in van der Waals heterostructures
Physical Review Research,;Vol. 2(2020)
Journal article
A. M. Hoque, B. Zhao, D. Khokhriakov, P. Muduli, and S. P. Dash, “Charge to Spin Conversion in van derWaalsMetal NbSe2”.
All-electrical creation and control of spin-galvanic signal in graphene and molybdenum ditelluride heterostructures at room temperature
Communications Physics,;Vol. 4(2021)
Journal article
Spin-valley coupling and spin-relaxation anisotropy in all-CVD Graphene- MoS2 van der Waals heterostructure
Physical Review Materials,;Vol. 7(2023)
Journal article
A. M. Hoque, A. Poliakov, A. V. Agrawal, B. Zhao, R. Mitra, S. Kubatkin, S. Lara-Avila, T. O. Shegai, and S. P. Dash, “Ultra-narrow Semiconductor WS2 Nanoribbon Field-effect Transistors with Atomically Designed Zig-zag Edges”.
The integration of memory and logic functionalities like the brain can reduce the energy loss associated with transferring data between memory and processor units, cut the time needed for computing operations and shrink the amount of space required on chips. Conventional materials (silicon) based current computation device is unsuitable to integrate logic and memory functionality locally in compact device design. In this thesis, I investigated the spin and charge transport in the newly developed two-dimensional (2D) materials for future memory and logic technologies. To mention, spin is a basic quantum property of an electron similar to its charge property. 2D materials such as graphene, semiconductors, and semimetals exhibit remarkable new properties that promise to integrate non-volatile memory and logic functionalities with lower energy consumption. One of the key aspects of spin-dependent device applications is to realize robust spin-charge conversion in 2D materials, for example, to read and write data in the memory cell. In this thesis, I show charge-to-spin interconversion phenomena in 2D materials for memory and logic applications. Interestingly a memory unit is accompanied by a field-effect transistor (FET) to access a particular memory cell. Hence, all 2D material-based memory applications will require 2D semiconductor material-based FETs. In this regard, this thesis presents transistor transport properties in 2D semiconductors (WS2, MoS2) with nanoribbon channels and with graphene contacts. These studies in 2D materials will be beneficial to develop nanometer-scale memory, logic and sensing technologies.
Graphene Core Project 3 (Graphene Flagship)
European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.
Spintronics with Topological Quantum Material and Magnetic Heterostructures
Swedish Research Council (VR) (2021-04821), 2022-01-01 -- 2025-12-31.
2Dimensional van der Waals Spin-Orbit Torque Technology
Swedish Research Council (VR) (2021-05925), 2021-12-01 -- 2024-11-30.
2D material-based technology for industrial applications (2D-TECH)
VINNOVA (2019-00068), 2020-05-01 -- 2024-12-31.
GKN Aerospace Sweden (2D-tech), 2021-01-01 -- 2024-12-31.
Driving Forces
Sustainable development
Innovation and entrepreneurship
Areas of Advance
Nanoscience and Nanotechnology
Roots
Basic sciences
Subject Categories
Other Physics Topics
Nano Technology
Other Electrical Engineering, Electronic Engineering, Information Engineering
Condensed Matter Physics
Infrastructure
Chalmers Materials Analysis Laboratory
Nanofabrication Laboratory
ISBN
978-91-7905-752-7
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5218
Publisher
Chalmers
Kollektorn (A423), 4th floor, MC2, Kemiv¨agen 9
Opponent: Professor Luis E. Hueso, CIC nanoGUNE, Spain