| 1. |
- Laverock, J., et al.
(författare)
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Photoemission evidence for crossover from Peierls-like to Mott-like transition in highly strained VO2
- 2012
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 86:19
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Tidskriftsartikel (refereegranskat)abstract
- We present a spectroscopic study that reveals that the metal-insulator transition of strained VO2 thin films may be driven towards a purely electronic transition, which does not rely on the Peierls dimerization, by the application of mechanical strain. Comparison with a moderately strained system, which does involve the lattice, demonstrates the crossover from Peierls- to Mott-like transitions.
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| 2. |
- Laverock, J, et al.
(författare)
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Direct Observation of Decoupled Structural and Electronic Transitions and an Ambient Pressure Monocliniclike Metallic Phase of VO_{2}.
- 2014
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Ingår i: Physical Review Letters. - 1079-7114. ; 113:21
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Tidskriftsartikel (refereegranskat)abstract
- We report the simultaneous measurement of the structural and electronic components of the metal-insulator transition (MIT) of VO_{2} using electron and photoelectron spectroscopies and microscopies. We show that these evolve over different temperature scales, and are separated by an unusual monocliniclike metallic phase. Our results provide conclusive evidence that the new monocliniclike metallic phase, recently identified in high-pressure and nonequilibrium measurements, is accessible in the thermodynamic transition at ambient pressure, and we discuss the implications of these observations on the nature of the MIT in VO_{2}.
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| 3. |
- Laverock, J., et al.
(författare)
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Observation of Weakened V-V Dimers in the Monoclinic Metallic Phase of Strained VO2
- 2018
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Ingår i: Physical Review Letters. - 0031-9007. ; 121:25
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Tidskriftsartikel (refereegranskat)abstract
- Emergent order at mesoscopic length scales in condensed matter can provide fundamental insight into the underlying competing interactions and their relationship with the order parameter. Using spectromicroscopy, we show that mesoscopic stripe order near the metal-insulator transition (MIT) of strained VO2 represents periodic modulations in both crystal symmetry and V - V dimerization. Above the MIT, we unexpectedly find the long-range order of V - V dimer strength and crystal symmetry become dissociated beyond ≈200 nm, whereas the conductivity transition proceeds homogeneously in a narrow temperature range.
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| 4. |
- Laverock, J., et al.
(författare)
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Resonant Soft-X-Ray Emission as a Bulk Probe of Correlated Electron Behavior in Metallic SrxCa1-xVO3
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 111:4
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of electron correlation in SrxCa1-xVO3 has been studied using a combination of bulk-sensitive resonant soft x-ray emission spectroscopy, surface-sensitive photoemission spectroscopy, and ab initio band structure calculations. We show that the effect of electron correlation is enhanced at the surface. Strong incoherent Hubbard subbands are found to lie similar to 20% closer in energy to the coherent quasiparticle features in surface-sensitive photoemission spectroscopy measurements compared with those from bulk-sensitive resonant soft x-ray emission spectroscopy, and a similar to 10% narrowing of the overall bandwidth at the surface is also observed.
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| 5. |
- Polley, C. M., et al.
(författare)
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Observation of surface states on heavily indium-doped SnTe(111), a superconducting topological crystalline insulator
- 2016
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 93:7
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Tidskriftsartikel (refereegranskat)abstract
- The topological crystalline insulator tin telluride is known to host superconductivity when doped with indium (Sn1-xInxTe), and for low indium content (x=0.04) it is known that the topological surface states are preserved. Here we present the growth, characterization, and angle resolved photoemission spectroscopy analysis of samples with much heavier In doping (up to x≈0.4), a regime where the superconducting temperature is increased nearly fourfold. We demonstrate that despite strong p-type doping, Dirac-like surface states persist.
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| 6. |
- Laverock, J., et al.
(författare)
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k-resolved susceptibility function of 2H-TaSe2 from angle-resolved photoemission
- 2013
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 88:3
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Tidskriftsartikel (refereegranskat)abstract
- The connection between the Fermi surface and charge-density-wave (CDW) order is revisited in 2H-TaSe2. Using angle-resolved photoemission spectroscopy, ab initio band-structure calculations, and an accurate tight-binding model, we develop the empirical k-resolved susceptibility function, which we use to highlight states that contribute to the susceptibility for a particular q vector. We show that although the Fermi surface is involved in the peaks in the susceptibility associated with CDW order, it is not through conventional Fermi surface nesting, but rather through finite energy transitions from states located far from the Fermi level. Comparison with monolayer TaSe2 illustrates the different mechanisms that are involved in the absence of bilayer splitting.
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