Near-commensuration from intertwined charge density waves in single-layer TiSe2
When the period of an incommensurate charge density wave (ICDW) approaches a multiple of a lattice vector, the energy gain from locking the period can drive a transition into an intermediate near-commensurate (NC) state made of locally commensurate regions separated by phase slips of a complex CDW....
| Authors: | , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2026 |
| Country: | España |
| Institution: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repository: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/424624 |
| Online Access: | http://hdl.handle.net/10261/424624 |
| Access Level: | Open access |
| Keyword: | Near commensurate charge density waves Scanning tunneling microscopy 2D materials Transition metal dichalcogenides |
| Summary: | When the period of an incommensurate charge density wave (ICDW) approaches a multiple of a lattice vector, the energy gain from locking the period can drive a transition into an intermediate near-commensurate (NC) state made of locally commensurate regions separated by phase slips of a complex CDW. In TiSe2, a paradigmatic CDW system, incommensuration is believed to be induced by carrier doping, yet its putative NC state has never been imaged. Here we observe a striking NC state in ultraclean, doped monolayers of TiSe2, displaying an intricate network of unidirectional domain walls. Detailed analysis reveals that these are not phase slips of a complex CDW, but rather sign-changing Ising-type domain walls of two coupled real CDWs of different symmetry. In addition, these CDWs are coupled to an unexpected nematic modulation at the lattice Bragg peaks. TiSe2 is thus a rare example of a NC-CDW of two intertwined real modulations with nematicity. |
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