Effect of Cu intercalation and pressure on excitonic interaction in 1T-TiSe2

Abstract

1T-TiSe2 has a semimetallic band structure at room temperature and undergoes phase transition to a triple-q charge density wave (CDW) state with a commensurate superlattice structure (2a * 2a * 2c) below Tc ~ 200 K at ambient pressure. This phase transition is caused by cooperative phenomena involving electron-phonon and electron-hole (excitonic) interactions, and cannot be described by a standard CDW framework. By Cu intercalation or the application of pressure, this phase transition temperature is suppressed and superconductivity (SC) appears. However, it is not clear what kind of order parameters are affected by these two procedures. We investigated the crystal structure of CuxTiSe2 and pressurized 1T-TiSe2 around the SC state by synchrotron x-ray diffraction on single crystals. In the high-temperature phase, the variation of structural parameters for the case of Cu intercalation and application of pressure are considerably different. Moreover, the relationship between the critical points of the CDW phase transition and the SC dome are also different for the two cases. The excitonic interaction appears to play an important role in the P-T phase diagram of 1T-TiSe2, but not in the x-T phase diagram.

arXiv comment11 pages, 7 figures, 1 table

References in corpus (31)

• Superconductivity in Cu_xTiSe_2
• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Controlling many-body states by the electric-field effect in a two-dimensional material
• Signatures of exciton condensation in a transition metal dichalcogenide
• Non-thermal separation of electronic and structural orders in a persisting charge density wave
• Charge density wave and superconducting dome in TiSe2 from electron-phonon interaction
• Orthorhombic-to-Monoclinic Phase Transition of Ta2NiSe5 Induced by the Bose-Einstein Condensation of Excitons
• Ultrafast Electronic Band Gap Control in an Excitonic Insulator
• Chiral charge-density-waves
• Electron-Phonon Coupling and the Soft Phonon Mode in TiSe${}_2$
• Coherent Order Parameter Oscillations in the Ground State of the Excitonic Insulator Ta2NiSe5
• Toroidal order in metals without local inversion symmetry
• Emergence of Fermi pockets in an excitonic CDW melted novel superconductor
• Influence of domain walls in the incommensurate charge density wave state of Cu intercalated 1$T$-TiSe${}_2$
• Observation of a Charge Density Wave Incommensuration Near the Superconducting Dome in CuxTiSe2
• Quantum Melting of the Charge Density Wave State in 1T-TiSe2
• Evolution of the Electronic Structure of 1T-CuxTiSe2
• Photo-induced enhancement of excitonic order
• Quantum and classical mode softening near the charge-density-wave/superconductor transition of Cu${}_x$TiSe${}_2$: Raman spectroscopic studies
• Electronic and vibrational properties of ${\text{TiSe}}_2$ in the charge-density wave phase from first principles
• Electron-Phonon Coupling Mode in Excitonic Insulator
• Critical role of the exchange interaction for the electronic structure and charge-density-wave formation in TiSe2
• Stripe and short range order in the charge density wave of 1T-Cu${}_x$TiSe${}_2$
• Exciton-phonon cooperative mechanism of the triple-$q$ charge-density-wave and antiferroelectric electron polarization in TiSe${}_2$
• Superconductivity at 2.3 K in the misfit compound (PbSe)1.16(TiSe2)2
• Electronic structure of copper intercalated transition metal dichalcogenides: First-principles calculations
• Superconductivity and hybrid soft modes in TiSe${}_2$
• Charge Transfer Effects in Naturally Occurring van der Waals Heterostructures (PbSe)1.16(TiSe2)m (m=1, 2)
• New Lithium- and Diamines-Intercalated Superconductors Li${}_x$(C${}_2$H${}_8$N${}_2$)${}_y$TiSe${}_2$ and Li${}_x$(C${}_6$H${}_{16}$N${}_2$)${}_y$TiSe${}_2$
• Anomalous metallic state of Cu${}_{0.07}$TiSe${}_2$: an optical spectroscopy study
• Varying Cu-Ti hybridization near the Fermi energy in Cu${}_x$TiSe${}_2$: Results from supercell calculations

Cited by in corpus (10)

• A New Era of Excitonic Insulators
• Structurally assisted melting of excitonic correlations in 1T-TiSe2
• Correlation between electronic and structural orders in 1T-TiSe2
• Unconventional Charge-density-wave Order in a Dilute d-band Semiconductor
• Observation of giant circular dichroism induced by electronic chirality
• Lifshitz transition enabling superconducting dome around the quantum critical point in TiSe${}_2$
• Non-chiral 1T-TiSe2 creates circular dichroism in resonant X-ray diffraction via multipole scattering interference
• Enhanced superconductivity with possible re-appearance of charge density wave states in polycrystalline Cu${}_{1-x}$Ag${}_x$Ir${}_2$Te${}_4$ alloys
• The maximal superconductivity in proximity to charge density wave quantum critical point in Cu${}_x$TiSe${}_2$
• Revisiting the charge-density-wave superlattice of 1$T$-TiSe${}_2$