Warmth can induce a number of section transitions in topological insulators, providing a novel, non-structural technique to manage topological phases
Topological insulators are supplies that behave as insulators of their inside however assist the movement of electrons alongside their edges or surfaces. These edge states are protected in opposition to weak dysfunction, corresponding to impurities, however might be disrupted by robust dysfunction. Not too long ago, researchers have explored a brand new class of supplies generally known as topological Anderson insulators. In these techniques, robust dysfunction results in Anderson localization, which prevents wave propagation within the bulk whereas nonetheless permitting strong edge conduction.
The Fermi power is the best power an electron can have in a fabric at absolute zero temperature. If the Fermi power lies in a conductive area, the fabric will conduct; if it lies in a ‘hole’, the fabric might be insulating. In a standard topological insulator, the Fermi power sits throughout the band hole. In topological Anderson insulators, it sits throughout the mobility hole quite than the standard band hole, making the sting states extremely steady. Electrons can exist within the mobility hole (not like within the band hole), however they’re localized and trapped. Till now, the transition from a topological insulator to a topological Anderson insulator has solely been achieved by structural modifications, which limits the flexibility to tune the fabric’s properties.
On this examine, the authors current each theoretical and experimental proof that this section transition might be induced by making use of warmth. Heating introduces power change with the setting, making the system non-Hermitian. This method supplies a brand new strategy to management the topological state of a fabric with out altering its construction. Additional heating prompts a second section transition, from a topological Anderson insulator to an Anderson insulator, the place all digital states turn out to be localized, and the fabric turns into totally insulating with no edge conduction.
This analysis deepens our understanding of how dysfunction influences topological phases and introduces a novel technique for engineering and tuning these phases utilizing thermal results. It additionally supplies a strong device for modulating electron conductivity by a easy, non-invasive method.
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Interacting topological insulators: a evaluate by Stephan Rachel (2018)
