A stable three-dimensional topological Dirac semimetal Cd3As2
A state of matter known as a three-dimensional Dirac semimetal has latterly garnered significant theoretical and experimental attention. Using angle-resolved photoelectron spectroscopy, it is shown that Cd 3 As 2 is an experimental realization of a three-dimensional Dirac semimetal that is stable at...
Gespeichert in:
| Veröffentlicht in: | Nature materials 2014-07, Vol.13 (7), p.677-681 |
|---|---|
| Hauptverfasser: | , , , , , , , , , , , , , , , , , |
| Format: | Artikel |
| Sprache: | eng |
| Schlagworte: | |
| Online-Zugang: | Volltext |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| container_end_page | 681 |
|---|---|
| container_issue | 7 |
| container_start_page | 677 |
| container_title | Nature materials |
| container_volume | 13 |
| creator | Liu, Z. K. Jiang, J. Zhou, B. Wang, Z. J. Zhang, Y. Weng, H. M. Prabhakaran, D. Mo, S-K. Peng, H. Dudin, P. Kim, T. Hoesch, M. Fang, Z. Dai, X. Shen, Z. X. Feng, D. L. Hussain, Z. Chen, Y. L. |
| description | A state of matter known as a three-dimensional Dirac semimetal has latterly garnered significant theoretical and experimental attention. Using angle-resolved photoelectron spectroscopy, it is shown that Cd
3
As
2
is an experimental realization of a three-dimensional Dirac semimetal that is stable at ambient conditions.
Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter
1
,
2
,
3
,
4
,
5
,
6
that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals
1
,
7
, axion insulators
1
,
4
and topological superconductors
8
,
9
), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd
3
As
2
, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO
2
(ref.
3
) and Na
3
Bi (refs
4
,
5
), Cd
3
As
2
is stable and has much higher Fermi velocities. Furthermore, by
in situ
doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena. |
| doi_str_mv | 10.1038/nmat3990 |
| format | Article |
| fullrecord | <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_miscellaneous_1539468938</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>3415738251</sourcerecordid><originalsourceid>FETCH-LOGICAL-c411t-e2b6f58158af4384ee70b9969a675e17d1ad3f431a89e82ad7b303e54787d0543</originalsourceid><addsrcrecordid>eNpdkEtLw0AUhQdRbK2Cv0ACbnQRnfdj4aLUJxTc6DpMkpuakmTqTLLov3dKW5Wu7rmcj3O5B6FLgu8IZvq-a23PjMFHaEy4kimXEh_vNCGUjtBZCEuMKRFCnqIR5VoYyekYPUyT0Nu8gaT_8gBpWbfQhdp1tkl6t3KNW9RF1I-1t0USoI1-H_dZyaaBnqOTyjYBLnZzgj6fnz5mr-n8_eVtNp2nBSekT4HmshKaCG0rzjQHUDg3RhorlQCiSmJLFh1itQFNbalyhhkIrrQqseBsgm62uSvvvgcIfdbWoYCmsR24IWREMMOlNkxH9PoAXbrBx3c2lFCSKm7wX2DhXQgeqmzl69b6dUZwtqk021ca0atd4JC3UP6C-w4jcLsFQrS6Bfh_Fw_DfgDnE30K</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1557627490</pqid></control><display><type>article</type><title>A stable three-dimensional topological Dirac semimetal Cd3As2</title><source>SpringerLink Journals</source><source>Nature Journals Online</source><creator>Liu, Z. K. ; Jiang, J. ; Zhou, B. ; Wang, Z. J. ; Zhang, Y. ; Weng, H. M. ; Prabhakaran, D. ; Mo, S-K. ; Peng, H. ; Dudin, P. ; Kim, T. ; Hoesch, M. ; Fang, Z. ; Dai, X. ; Shen, Z. X. ; Feng, D. L. ; Hussain, Z. ; Chen, Y. L.</creator><creatorcontrib>Liu, Z. K. ; Jiang, J. ; Zhou, B. ; Wang, Z. J. ; Zhang, Y. ; Weng, H. M. ; Prabhakaran, D. ; Mo, S-K. ; Peng, H. ; Dudin, P. ; Kim, T. ; Hoesch, M. ; Fang, Z. ; Dai, X. ; Shen, Z. X. ; Feng, D. L. ; Hussain, Z. ; Chen, Y. L.</creatorcontrib><description>A state of matter known as a three-dimensional Dirac semimetal has latterly garnered significant theoretical and experimental attention. Using angle-resolved photoelectron spectroscopy, it is shown that Cd
3
As
2
is an experimental realization of a three-dimensional Dirac semimetal that is stable at ambient conditions.
Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter
1
,
2
,
3
,
4
,
5
,
6
that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals
1
,
7
, axion insulators
1
,
4
and topological superconductors
8
,
9
), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd
3
As
2
, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO
2
(ref.
3
) and Na
3
Bi (refs
4
,
5
), Cd
3
As
2
is stable and has much higher Fermi velocities. Furthermore, by
in situ
doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.</description><identifier>ISSN: 1476-1122</identifier><identifier>EISSN: 1476-4660</identifier><identifier>DOI: 10.1038/nmat3990</identifier><identifier>PMID: 24859642</identifier><language>eng</language><publisher>London: Nature Publishing Group UK</publisher><subject>140/146 ; 639/301/1005/1007 ; 639/301/119/995 ; 639/766/119/2792 ; Biomaterials ; Carbon ; Condensed Matter Physics ; letter ; Materials Science ; Matter & antimatter ; Metals ; Nanotechnology ; Optical and Electronic Materials ; Physics ; Quantum physics ; Spectroscopy ; Three dimensional imaging ; Topology</subject><ispartof>Nature materials, 2014-07, Vol.13 (7), p.677-681</ispartof><rights>Springer Nature Limited 2014</rights><rights>Copyright Nature Publishing Group Jul 2014</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c411t-e2b6f58158af4384ee70b9969a675e17d1ad3f431a89e82ad7b303e54787d0543</citedby><cites>FETCH-LOGICAL-c411t-e2b6f58158af4384ee70b9969a675e17d1ad3f431a89e82ad7b303e54787d0543</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://link.springer.com/content/pdf/10.1038/nmat3990$$EPDF$$P50$$Gspringer$$H</linktopdf><linktohtml>$$Uhttps://link.springer.com/10.1038/nmat3990$$EHTML$$P50$$Gspringer$$H</linktohtml><link.rule.ids>314,776,780,27901,27902,41464,42533,51294</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/24859642$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Liu, Z. K.</creatorcontrib><creatorcontrib>Jiang, J.</creatorcontrib><creatorcontrib>Zhou, B.</creatorcontrib><creatorcontrib>Wang, Z. J.</creatorcontrib><creatorcontrib>Zhang, Y.</creatorcontrib><creatorcontrib>Weng, H. M.</creatorcontrib><creatorcontrib>Prabhakaran, D.</creatorcontrib><creatorcontrib>Mo, S-K.</creatorcontrib><creatorcontrib>Peng, H.</creatorcontrib><creatorcontrib>Dudin, P.</creatorcontrib><creatorcontrib>Kim, T.</creatorcontrib><creatorcontrib>Hoesch, M.</creatorcontrib><creatorcontrib>Fang, Z.</creatorcontrib><creatorcontrib>Dai, X.</creatorcontrib><creatorcontrib>Shen, Z. X.</creatorcontrib><creatorcontrib>Feng, D. L.</creatorcontrib><creatorcontrib>Hussain, Z.</creatorcontrib><creatorcontrib>Chen, Y. L.</creatorcontrib><title>A stable three-dimensional topological Dirac semimetal Cd3As2</title><title>Nature materials</title><addtitle>Nature Mater</addtitle><addtitle>Nat Mater</addtitle><description>A state of matter known as a three-dimensional Dirac semimetal has latterly garnered significant theoretical and experimental attention. Using angle-resolved photoelectron spectroscopy, it is shown that Cd
3
As
2
is an experimental realization of a three-dimensional Dirac semimetal that is stable at ambient conditions.
Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter
1
,
2
,
3
,
4
,
5
,
6
that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals
1
,
7
, axion insulators
1
,
4
and topological superconductors
8
,
9
), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd
3
As
2
, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO
2
(ref.
3
) and Na
3
Bi (refs
4
,
5
), Cd
3
As
2
is stable and has much higher Fermi velocities. Furthermore, by
in situ
doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.</description><subject>140/146</subject><subject>639/301/1005/1007</subject><subject>639/301/119/995</subject><subject>639/766/119/2792</subject><subject>Biomaterials</subject><subject>Carbon</subject><subject>Condensed Matter Physics</subject><subject>letter</subject><subject>Materials Science</subject><subject>Matter & antimatter</subject><subject>Metals</subject><subject>Nanotechnology</subject><subject>Optical and Electronic Materials</subject><subject>Physics</subject><subject>Quantum physics</subject><subject>Spectroscopy</subject><subject>Three dimensional imaging</subject><subject>Topology</subject><issn>1476-1122</issn><issn>1476-4660</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2014</creationdate><recordtype>article</recordtype><sourceid>BENPR</sourceid><recordid>eNpdkEtLw0AUhQdRbK2Cv0ACbnQRnfdj4aLUJxTc6DpMkpuakmTqTLLov3dKW5Wu7rmcj3O5B6FLgu8IZvq-a23PjMFHaEy4kimXEh_vNCGUjtBZCEuMKRFCnqIR5VoYyekYPUyT0Nu8gaT_8gBpWbfQhdp1tkl6t3KNW9RF1I-1t0USoI1-H_dZyaaBnqOTyjYBLnZzgj6fnz5mr-n8_eVtNp2nBSekT4HmshKaCG0rzjQHUDg3RhorlQCiSmJLFh1itQFNbalyhhkIrrQqseBsgm62uSvvvgcIfdbWoYCmsR24IWREMMOlNkxH9PoAXbrBx3c2lFCSKm7wX2DhXQgeqmzl69b6dUZwtqk021ca0atd4JC3UP6C-w4jcLsFQrS6Bfh_Fw_DfgDnE30K</recordid><startdate>20140701</startdate><enddate>20140701</enddate><creator>Liu, Z. K.</creator><creator>Jiang, J.</creator><creator>Zhou, B.</creator><creator>Wang, Z. J.</creator><creator>Zhang, Y.</creator><creator>Weng, H. M.</creator><creator>Prabhakaran, D.</creator><creator>Mo, S-K.</creator><creator>Peng, H.</creator><creator>Dudin, P.</creator><creator>Kim, T.</creator><creator>Hoesch, M.</creator><creator>Fang, Z.</creator><creator>Dai, X.</creator><creator>Shen, Z. X.</creator><creator>Feng, D. L.</creator><creator>Hussain, Z.</creator><creator>Chen, Y. L.</creator><general>Nature Publishing Group UK</general><general>Nature Publishing Group</general><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>3V.</scope><scope>7SR</scope><scope>7X7</scope><scope>7XB</scope><scope>88E</scope><scope>88I</scope><scope>8AO</scope><scope>8BQ</scope><scope>8FD</scope><scope>8FE</scope><scope>8FG</scope><scope>8FI</scope><scope>8FJ</scope><scope>8FK</scope><scope>ABJCF</scope><scope>ABUWG</scope><scope>AEUYN</scope><scope>AFKRA</scope><scope>AZQEC</scope><scope>BENPR</scope><scope>BGLVJ</scope><scope>CCPQU</scope><scope>D1I</scope><scope>DWQXO</scope><scope>FYUFA</scope><scope>GHDGH</scope><scope>GNUQQ</scope><scope>HCIFZ</scope><scope>JG9</scope><scope>K9.</scope><scope>KB.</scope><scope>L6V</scope><scope>M0S</scope><scope>M1P</scope><scope>M2P</scope><scope>M7S</scope><scope>PDBOC</scope><scope>PHGZM</scope><scope>PHGZT</scope><scope>PJZUB</scope><scope>PKEHL</scope><scope>PPXIY</scope><scope>PQEST</scope><scope>PQGLB</scope><scope>PQQKQ</scope><scope>PQUKI</scope><scope>PTHSS</scope><scope>Q9U</scope><scope>7X8</scope></search><sort><creationdate>20140701</creationdate><title>A stable three-dimensional topological Dirac semimetal Cd3As2</title><author>Liu, Z. K. ; Jiang, J. ; Zhou, B. ; Wang, Z. J. ; Zhang, Y. ; Weng, H. M. ; Prabhakaran, D. ; Mo, S-K. ; Peng, H. ; Dudin, P. ; Kim, T. ; Hoesch, M. ; Fang, Z. ; Dai, X. ; Shen, Z. X. ; Feng, D. L. ; Hussain, Z. ; Chen, Y. L.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c411t-e2b6f58158af4384ee70b9969a675e17d1ad3f431a89e82ad7b303e54787d0543</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2014</creationdate><topic>140/146</topic><topic>639/301/1005/1007</topic><topic>639/301/119/995</topic><topic>639/766/119/2792</topic><topic>Biomaterials</topic><topic>Carbon</topic><topic>Condensed Matter Physics</topic><topic>letter</topic><topic>Materials Science</topic><topic>Matter & antimatter</topic><topic>Metals</topic><topic>Nanotechnology</topic><topic>Optical and Electronic Materials</topic><topic>Physics</topic><topic>Quantum physics</topic><topic>Spectroscopy</topic><topic>Three dimensional imaging</topic><topic>Topology</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Liu, Z. K.</creatorcontrib><creatorcontrib>Jiang, J.</creatorcontrib><creatorcontrib>Zhou, B.</creatorcontrib><creatorcontrib>Wang, Z. J.</creatorcontrib><creatorcontrib>Zhang, Y.</creatorcontrib><creatorcontrib>Weng, H. M.</creatorcontrib><creatorcontrib>Prabhakaran, D.</creatorcontrib><creatorcontrib>Mo, S-K.</creatorcontrib><creatorcontrib>Peng, H.</creatorcontrib><creatorcontrib>Dudin, P.</creatorcontrib><creatorcontrib>Kim, T.</creatorcontrib><creatorcontrib>Hoesch, M.</creatorcontrib><creatorcontrib>Fang, Z.</creatorcontrib><creatorcontrib>Dai, X.</creatorcontrib><creatorcontrib>Shen, Z. X.</creatorcontrib><creatorcontrib>Feng, D. L.</creatorcontrib><creatorcontrib>Hussain, Z.</creatorcontrib><creatorcontrib>Chen, Y. L.</creatorcontrib><collection>PubMed</collection><collection>CrossRef</collection><collection>ProQuest Central (Corporate)</collection><collection>Engineered Materials Abstracts</collection><collection>Health & Medical Collection</collection><collection>ProQuest Central (purchase pre-March 2016)</collection><collection>Medical Database (Alumni Edition)</collection><collection>Science Database (Alumni Edition)</collection><collection>ProQuest Pharma Collection</collection><collection>METADEX</collection><collection>Technology Research Database</collection><collection>ProQuest SciTech Collection</collection><collection>ProQuest Technology Collection</collection><collection>Hospital Premium Collection</collection><collection>Hospital Premium Collection (Alumni Edition)</collection><collection>ProQuest Central (Alumni) (purchase pre-March 2016)</collection><collection>Materials Science & Engineering Collection</collection><collection>ProQuest Central (Alumni Edition)</collection><collection>ProQuest One Sustainability</collection><collection>ProQuest Central UK/Ireland</collection><collection>ProQuest Central Essentials</collection><collection>ProQuest Central</collection><collection>Technology Collection</collection><collection>ProQuest One Community College</collection><collection>ProQuest Materials Science Collection</collection><collection>ProQuest Central Korea</collection><collection>Health Research Premium Collection</collection><collection>Health Research Premium Collection (Alumni)</collection><collection>ProQuest Central Student</collection><collection>SciTech Premium Collection</collection><collection>Materials Research Database</collection><collection>ProQuest Health & Medical Complete (Alumni)</collection><collection>Materials Science Database</collection><collection>ProQuest Engineering Collection</collection><collection>Health & Medical Collection (Alumni Edition)</collection><collection>Medical Database</collection><collection>Science Database</collection><collection>Engineering Database</collection><collection>Materials Science Collection</collection><collection>ProQuest Central (New)</collection><collection>ProQuest One Academic (New)</collection><collection>ProQuest Health & Medical Research Collection</collection><collection>ProQuest One Academic Middle East (New)</collection><collection>ProQuest One Health & Nursing</collection><collection>ProQuest One Academic Eastern Edition (DO NOT USE)</collection><collection>ProQuest One Applied & Life Sciences</collection><collection>ProQuest One Academic</collection><collection>ProQuest One Academic UKI Edition</collection><collection>Engineering Collection</collection><collection>ProQuest Central Basic</collection><collection>MEDLINE - Academic</collection><jtitle>Nature materials</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Liu, Z. K.</au><au>Jiang, J.</au><au>Zhou, B.</au><au>Wang, Z. J.</au><au>Zhang, Y.</au><au>Weng, H. M.</au><au>Prabhakaran, D.</au><au>Mo, S-K.</au><au>Peng, H.</au><au>Dudin, P.</au><au>Kim, T.</au><au>Hoesch, M.</au><au>Fang, Z.</au><au>Dai, X.</au><au>Shen, Z. X.</au><au>Feng, D. L.</au><au>Hussain, Z.</au><au>Chen, Y. L.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>A stable three-dimensional topological Dirac semimetal Cd3As2</atitle><jtitle>Nature materials</jtitle><stitle>Nature Mater</stitle><addtitle>Nat Mater</addtitle><date>2014-07-01</date><risdate>2014</risdate><volume>13</volume><issue>7</issue><spage>677</spage><epage>681</epage><pages>677-681</pages><issn>1476-1122</issn><eissn>1476-4660</eissn><abstract>A state of matter known as a three-dimensional Dirac semimetal has latterly garnered significant theoretical and experimental attention. Using angle-resolved photoelectron spectroscopy, it is shown that Cd
3
As
2
is an experimental realization of a three-dimensional Dirac semimetal that is stable at ambient conditions.
Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter
1
,
2
,
3
,
4
,
5
,
6
that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals
1
,
7
, axion insulators
1
,
4
and topological superconductors
8
,
9
), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd
3
As
2
, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO
2
(ref.
3
) and Na
3
Bi (refs
4
,
5
), Cd
3
As
2
is stable and has much higher Fermi velocities. Furthermore, by
in situ
doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.</abstract><cop>London</cop><pub>Nature Publishing Group UK</pub><pmid>24859642</pmid><doi>10.1038/nmat3990</doi><tpages>5</tpages></addata></record> |
| fulltext | fulltext |
| identifier | ISSN: 1476-1122 |
| ispartof | Nature materials, 2014-07, Vol.13 (7), p.677-681 |
| issn | 1476-1122 1476-4660 |
| language | eng |
| recordid | cdi_proquest_miscellaneous_1539468938 |
| source | SpringerLink Journals; Nature Journals Online |
| subjects | 140/146 639/301/1005/1007 639/301/119/995 639/766/119/2792 Biomaterials Carbon Condensed Matter Physics letter Materials Science Matter & antimatter Metals Nanotechnology Optical and Electronic Materials Physics Quantum physics Spectroscopy Three dimensional imaging Topology |
| title | A stable three-dimensional topological Dirac semimetal Cd3As2 |
| url | https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-02-20T13%3A50%3A47IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-proquest_cross&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=A%20stable%20three-dimensional%20topological%20Dirac%20semimetal%20Cd3As2&rft.jtitle=Nature%20materials&rft.au=Liu,%20Z.%20K.&rft.date=2014-07-01&rft.volume=13&rft.issue=7&rft.spage=677&rft.epage=681&rft.pages=677-681&rft.issn=1476-1122&rft.eissn=1476-4660&rft_id=info:doi/10.1038/nmat3990&rft_dat=%3Cproquest_cross%3E3415738251%3C/proquest_cross%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_pqid=1557627490&rft_id=info:pmid/24859642&rfr_iscdi=true |