{"id":66,"date":"2025-08-27T12:00:04","date_gmt":"2025-08-27T10:00:04","guid":{"rendered":"https:\/\/members.ifimac.uam.es\/stm2d\/?p=66"},"modified":"2025-10-21T17:16:54","modified_gmt":"2025-10-21T15:16:54","slug":"observation-charge-density-wave-excitonic-order-parameter-in-topological-insulator-wte2","status":"publish","type":"post","link":"https:\/\/members.ifimac.uam.es\/stm2d\/research-highlights\/observation-charge-density-wave-excitonic-order-parameter-in-topological-insulator-wte2\/","title":{"rendered":"Observation of the Charge Density Wave Excitonic Order Parameter in Topological Insulator Monolayer WTe2"},"content":{"rendered":"<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/pubs.acs.org\/cms\/10.1021\/acsnano.5c08005\/asset\/images\/medium\/nn5c08005_0005.gif\" alt=\"\" width=\"567\" height=\"235\" \/><\/p>\n<p style=\"text-align: justify\"><span class=\"dropcap\">S<\/span>trong electron\u2212hole interactions in a semimetal or narrow-gap semiconductor may drive a ground state of condensed excitons. Monolayer WTe<sub>2<\/sub> has been proposed as a host material for such an exciton condensate, but the order parameter, the key signature of a macroscopic quantumcoherent condensate, has not been observed. Here, we use Fourier-transform scanning tunneling spectroscopy (FT-STS) to study quasiparticle interference (QPI) and periodic modulations of the local density of states (LDOS) in monolayer WTe<sub>2<\/sub>. In WTe<sub>2<\/sub> on graphene, in which the carrier density can be varied via back-gating, FT-STS shows QPI features in the two-dimensional (2D) bulk bands, confirming the interacting nature of the bandgap in neutral WTe<sub>2<\/sub> and the semimetallic nature of highly n- and p-doped WTe<sub>2<\/sub>. We observe additional nondispersive spatial modulations in the LDOS imprinted on the topological edge mode of neutral WTe<sub>2<\/sub> on metallic substrates (graphene and graphite), which we interpret as the interaction of the topological edge mode with the expected charge density wave order parameter of the excitonic condensate in WTe<sub>2<\/sub> at low interaction strength due to screening by the metallic substrates.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Strong electron\u2212hole interactions in a semimetal or narrow-gap semiconductor may drive a ground state of condensed excitons. Monolayer WTe2 has been proposed as a host material for such an exciton condensate, but the order parameter, the key signature of a macroscopic quantumcoherent condensate, has not been observed. Here, we use Fourier-transform scanning tunneling spectroscopy (FT-STS)&hellip;<\/p>\n","protected":false},"author":17,"featured_media":104,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_mo_disable_npp":"","footnotes":""},"categories":[5,4],"tags":[14,16,13,17,15],"class_list":["post-66","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles","category-research-highlights","tag-charge-density-wave","tag-edge-state","tag-excitonic-order-parameter","tag-monolyer-tungsten-ditelluride","tag-topological-excitonic-insultor","entry"],"_links":{"self":[{"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/posts\/66","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/users\/17"}],"replies":[{"embeddable":true,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/comments?post=66"}],"version-history":[{"count":10,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/posts\/66\/revisions"}],"predecessor-version":[{"id":244,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/posts\/66\/revisions\/244"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/media\/104"}],"wp:attachment":[{"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/media?parent=66"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/categories?post=66"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/members.ifimac.uam.es\/stm2d\/wp-json\/wp\/v2\/tags?post=66"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}