"Version: 20250501"--Title page verso.Includes bibliographical references.1. Introduction to two-dimensional (2D) materials and valleytronics -- 1.1. Introduction -- 1.2. Electronic properties of graphene, definition of 'valley' -- 1.3. Electronic properties of zigzag graphene nanoribbons -- 1.4. Spin-orbit coupling in 2D materials -- 1.5. Molybdenum disulfide (MoS2) and the transition-metal di…