2021/11/25 by Panagiotis Kotetes, Kotetes, Panagiotis
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Atomic and Subatomic Physics Research #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Graphene research and applications #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2111.12957
openalex publication_date 2021/11/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This work brings forward an alternative experimental approach to infer the\ntopological character of phase transitions in insulators. This method relies on\nsubjecting the target system to a set of external fields, each of which\nconsists of two parts, i.e., a weak spatiotemporally slowly-varying component\non top of a constant offset. The fields are chosen in such a way, so that they\nrespectively induce slow variations in the wave vector describing the bulk band\nstructure, as well as a parameter which allows tuning the bulk gap. Such a\nprocess maps the Berry singularities of the base space to a synthetic space\nspanned by the parameters related to the external fields. By measuring the\nresponse of the system to the weak part of the perturbations, when these are\nadditionally chosen to form spacetime textures, one can construct a quantity\nthat is here-termed Berry singularity marker (BSM). The BSM enables the Berry\nsingularity detection as it becomes nonzero only in the close vicinity of a\nBerry singularity and is equal to its charge. The calculation of the BSM\nrequires the measurement of the susceptibility tensor for the applied external\nfields. Near the Berry singularities, the BSM is dominated by a universal\nvalue, which is determined by the quantum metric tensor of the system. While in\nthis work I restrict to 1D AIII insulators, the proposed approach is general.\nNotably, a key feature of the present method is that it can be implemented in a\nlock-in fashion, that is, one can "filter out" from the BSM any possible\ncontribution from disorder by performing more measurements. Hence, the present\nconstruction paves the way for a disorder resilient diagnosis of topological\nphase transitions, that appears particularly relevant for disordered\ntopological insulator and hybrid Majorana platforms, while it can be readily\nimplemented using topo-electric circuits.\n