Atomic force microscopy; Correlated electrons; Superconductivity; Scanning tunneling microscopy; Intercalated graphite superconductors; Charge density waves; Vortex cores; Scanning tunneling spectroscopy; Transition metal dichalcogenides; Stripes; Cuprate high temperature superconductors
Martinez-Castro Jose, Mauro Diego, Pásztor Árpád, Gutiérrez-Lezama Ignacio, Scarfato Alessandro, Morpurgo Alberto F., Renner Christoph (2018), Scanning Tunneling Microscopy of an Air Sensitive Dichalcogenide Through an Encapsulating Layer, in Nano Letters
, 18(11), 6696-6702.
Ponomarev Evgeniy, Pásztor Árpád, Waelchli Adrien, Scarfato Alessandro, Ubrig Nicolas, Renner Christoph, Morpurgo Alberto F. (2018), Hole Transport in Exfoliated Monolayer MoS 2, in ACS Nano
, 12(3), 2669-2676.
Berthod Christophe, Maggio-Aprile Ivan, Bruér Jens, Erb Andreas, Renner Christoph (2017), Observation of Caroli–de Gennes–Matricon Vortex States in YBa2Cu3O7−δ, in Physical Review Letters
, 119(23), 237001-237001.
Pasztor A., Scarfato A., Renner Ch. (2017), Note: Mechanical in situ exfoliation of van der Waals materials, in Review of Scientific Instruments
, 88(7), 076104-1-076104-3.
Novello A. M., Spera M., Scarfato A., Ubaldini A., Giannini E., Bowler D. R., Renner Ch. (2017), Stripe and Short Range Order in the Charge Density Wave of 1T−CuxTiSe2, in Physical Review Letters
, 118(1), 017002-017002.
Árpád Pásztor, Scarfato Alessandro, Barreteau Céline, Giannini Enrico, Renner Christoph (2017), Dimensional crossover of the charge density wave transition in thin exfoliated VSe2, in 2D Materials
, 4(4), 041005-041005.
Bruér Jens, Maggio-Aprile Ivan, Jenkins Nathan, Ristić Zoran, Erb Andreas, Berthod Christophe, Fischer Øystein, Renner Christoph (2016), Revisiting the vortex-core tunnelling spectroscopy in YBa2Cu3O7−δ, in Nature Communications
, 7(1), 11139-11139.
Novello A. M., Hildebrand B., Scarfato A., Didiot C., Monney G., Ubaldini A., Berger H., Bowler D. R., Aebi P., Renner Ch. (2015), Scanning tunneling microscopy of the charge density wave in 1T-TiSe2 in the presence of single atom defects, in Physical Review B
, 92(8), 081101-1-081101-4.
Understanding and mastering high temperature superconductivity remains one of the mostexciting problems in contemporary solid state physics. This proposal aims to contribute tothe characterization and understanding of the distinctive pseudogap phase defining thenormal state of many unconventional layered superconductors. There is mounting evidencesfor charge ordering instabilities above the superconducting transition in cuprates and otherso-called high temperature superconductors. But the precise nature of this normal stateelectron matter that forms the breeding ground of superconductivity in these materials remainsthe subject of intense experimental and theoretical scrutiny.Recent results we have obtained on YBa2Cu3O7-d (Y-123) and 1T-CuxTiSe2 provide novel insightinto the charge ordered phases and their interplay with superconductivity. In Y-123,we find that the subgap states so far interpreted in terms of vortex core states are notbound to vortices. High resolution spectra reveal they are ubiquitous features of the tunnelingspectra measured with and without magnetic field. They could be spectroscopic signaturesof the charge ordering observed by other techniques, a hypothesis we want to explorein this proposal. In 1T-CuxTiSe2, we find evidences for a charge stripe instability when x>0. Here, the question is whether this lower symmetry ordered phase plays a role in the superconductingphase transition. These yet unpublished results prompt us to propose a newstudy of the pseudogap phase and associated electron matter by means of scanning probemicroscopy and spectroscopy. We shall take advantage of recent progress in material synthesisand scanning probe instrumentation to study the unconventional (ordered) normalstate above Tc as well as inside vortex cores below Tc. We are proposing new experimentalprotocols, investigating adjacent terraces to look for chirality and charge density wave(CDW) correlations along the c-axis, combining tunneling and point contact spectroscopy todelineate phase coherent and quasiparticle spectral features, and developing new instrumentationcapabilities such as applying tuneable strain to the sample.HTS cuprates have been the subject of sustained studies for nearly thirty years. But a generalconsensus on the mechanism of superconductivity and the nature of the normal state isstill lacking. YBaCu3O7-d and 1T-CuxTiSe2 share analogous phase diagrams where superconductivitydevelops on the vanishing edge of some ordered electron matter phase with arange of similar questions still to be answered. For example what drives the charge orderinginstabilities, what is the nature and driving mechanisms of the CDW, stripes and nematicphases; are they chiral; what is the nature of the normal state gap; does it compete, cooperateor simply coexist with superconductivity? We shall contribute to these issues in a parallelstudy of HTS cuprates and low temperature layered superconductors by STM and AFM,two techniques with unique capabilities to explore the spectral signatures and real spacetextures of the normal state electron matter. The likely outcome is not only a better understandingof the superconducting phase transition