{"created":"2023-05-15T15:03:18.356754+00:00","id":85756,"links":{},"metadata":{"_buckets":{"deposit":"dab682fe-fab0-4c92-8dff-b640ea2d4082"},"_deposit":{"created_by":1,"id":"85756","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"85756"},"status":"published"},"_oai":{"id":"oai:repo.qst.go.jp:00085756","sets":["10:29"]},"author_link":["1031992","1031994","1031988","1031995","1031989","1031993","1031991","1031990"],"item_10005_date_7":{"attribute_name":"発表年月日","attribute_value_mlt":[{"subitem_date_issued_datetime":"2022-03-25","subitem_date_issued_type":"Issued"}]},"item_10005_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Very short valley lifetimes (~10^3-10^6 femtoseconds (fs)) demands the ultrafast control of valley selection on fs time scale. In this work, we explore the possibility to induce valley asymmetry by single-cycle linearly polarized laser pulse in WSe2 monolayer. By combining the time-dependent density functional theory with the two-band massive Dirac Hamiltonian, we study the various factors that are vital for valley polarization by linearly polarized laser pulse both in linear and non-linear optics limits.\nIn contrast to long pulses, ultrashort pulses containing few optical cycles, the condition (maxima of E(t)=0 of A(t)) can be controlled by CEP (φ). φ is the relative phase of the pulse envelope and the oscillating electric field which plays a significant role in the pulse waveform for ultrashort laser pulses. To explore the φ dependence on valley pseudospin, we apply linearly polarized pulses parallel to armchair (Γ-M) and zigzag (Γ-K) directions. Valley polarization does not exist for the field polarized along Γ-M because of the lattice symmetry in that direction. On the other hand, owing to trigonal wrapping, the polarization parallel to Γ-K experiences different band curvature with respect to K and K' point.\n The valley polarization for weak intensity is zero for all φ confirm the fact that the valley polarization is absent within the linear-optical limit. By increasing the intensity, we enter in the nonlinear regime and the substantial valley polarization is observed. The valley polarization increases gradually with φ and reaches its maximum value at φ = π/2, shows a typical sine wave curve. Valley polarization is robust against field strength but in all cases oscillate as a function of CEP. \nThe spin polarization (N _↑ - N _↓) is negligible and independent of intensity and φ. Degree of spin polarization (N _↑- N _↓) / (N _↑+ N _↓) follow the same behavior as valley polarization which shows that spin polarization is also an observable along with valley polarization.","subitem_description_type":"Abstract"}]},"item_10005_description_6":{"attribute_name":"会議概要（会議名, 開催地, 会期, 主催者等）","attribute_value_mlt":[{"subitem_description":"69th JSAP Spring Meeting 2022","subitem_description_type":"Other"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"metadata only access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_14cb"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Hashmi, Arqum"}],"nameIdentifiers":[{"nameIdentifier":"1031988","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Yamada, Shunsuke"}],"nameIdentifiers":[{"nameIdentifier":"1031989","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Yamada, Atsushi"}],"nameIdentifiers":[{"nameIdentifier":"1031990","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Kazuhiro, Yabana"}],"nameIdentifiers":[{"nameIdentifier":"1031991","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Tomohito, Otobe"}],"nameIdentifiers":[{"nameIdentifier":"1031992","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Hashmi, Arqum","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"1031993","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Kazuhiro, Yabana","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"1031994","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Tomohito, Otobe","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"1031995","nameIdentifierScheme":"WEKO"}]}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"conference object","resourceuri":"http://purl.org/coar/resource_type/c_c94f"}]},"item_title":"Ultrafast control of the valley and spin polarization in Transition-metal dichalcogenides","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Ultrafast control of the valley and spin polarization in Transition-metal dichalcogenides"}]},"item_type_id":"10005","owner":"1","path":["29"],"pubdate":{"attribute_name":"公開日","attribute_value":"2022-02-04"},"publish_date":"2022-02-04","publish_status":"0","recid":"85756","relation_version_is_last":true,"title":["Ultrafast control of the valley and spin polarization in Transition-metal dichalcogenides"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-05-15T17:38:47.481871+00:00"}