Nano- and Bio- Electronics: Topologically protected one-dimensional valley transport at two-dimensional semiconductor twin boundaries
Abstract
The concept of topology of electronic states in crystalline solids has revolutionized the classification of the electronic states of matter. A characteristic feature of topologically nontrivial materials is the existence of robust electronic states at sample boundaries that are protected by the bulk band topology. Although topologically nontrivial materials have been identified and realized, the bulk energy gap of these materials is generally small. Thus at elevated temperatures the bulk conduction channel is thermally activated and dominates. Consequently the topological transport phenomena have been observed only at low temperatures. To realize robust topological transport at elevated temperatures or even at room temperature, relevant for technological applications, topologically nontrivial materials with large energy gaps are needed. This project proposes to realize topologically protected one-dimensional conduction channels for valley transport at twin domain boundaries of large band gap monolayer transition metal dichalcogenides. This research will rely on the recent experimental advances achieved in the PT s lab and elsewhere on (i) the growth of monolayer transition metal dichalcogenides with sharp domain boundaries, (ii) the development of non-invasive and high-throughput optical techniques to identify twin domain boundaries, and (iii) the development of techniques to fabricate field-effect transistor devices of mono layer transition metal dichalcogenides with nanoscale contacts using the van der Waals heterostructure approach. These structures will be characterized using combined optical and electrical methods. The realization of topologically protected one-dimensional conduction modes will open up exciting opportunities for the exploration of topological phases in transition metal dichalcogenides including the one-dimensional interaction physics, the chiral anomaly, and the topological superconductivity. Such one-dimensional conduction modes with ballistic spin and valley transport can potentially also enable new ways to control the spin and valley degree of freedom for valleytronic and spintronic devices.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 16, 2018
- Source ID
- W911NF1710605
Entities
People
- Kin Fai Mak
Organizations
- Army Contracting Command
- Cornell University
- United States Army