TY  - JOUR
A1  - Hudson, Lawrence N.
A1  - Newbold, Tim
A1  - Contu, Sara
A1  - Hill, Samantha L. L.
A1  - Lysenko, Igor
A1  - De Palma, Adriana
A1  - Phillips, Helen R. P.
A1  - Senior, Rebecca A.
A1  - Bennett, Dominic J.
A1  - Booth, Hollie
A1  - Choimes, Argyrios
A1  - Correia, David L. P.
A1  - Day, Julie
A1  - Echeverria-Londono, Susy
A1  - Garon, Morgan
A1  - Harrison, Michelle L. K.
A1  - Ingram, Daniel J.
A1  - Jung, Martin
A1  - Kemp, Victoria
A1  - Kirkpatrick, Lucinda
A1  - Martin, Callum D.
A1  - Pan, Yuan
A1  - White, Hannah J.
A1  - Aben, Job
A1  - Abrahamczyk, Stefan
A1  - Adum, Gilbert B.
A1  - Aguilar-Barquero, Virginia
A1  - Aizen, Marcelo
A1  - Ancrenaz, Marc
A1  - Arbelaez-Cortes, Enrique
A1  - Armbrecht, Inge
A1  - Azhar, Badrul
A1  - Azpiroz, Adrian B.
A1  - Baeten, Lander
A1  - Báldi, András
A1  - Banks, John E.
A1  - Barlow, Jos
A1  - Batáry, Péter
A1  - Bates, Adam J.
A1  - Bayne, Erin M.
A1  - Beja, Pedro
A1  - Berg, Ake
A1  - Berry, Nicholas J.
A1  - Bicknell, Jake E.
A1  - Bihn, Jochen H.
A1  - Böhning-Gaese, Katrin
A1  - Boekhout, Teun
A1  - Boutin, Celine
A1  - Bouyer, Jeremy
A1  - Brearley, Francis Q.
A1  - Brito, Isabel
A1  - Brunet, Jörg
A1  - Buczkowski, Grzegorz
A1  - Buscardo, Erika
A1  - Cabra-Garcia, Jimmy
A1  - Calvino-Cancela, Maria
A1  - Cameron, Sydney A.
A1  - Cancello, Eliana M.
A1  - Carrijo, Tiago F.
A1  - Carvalho, Anelena L.
A1  - Castro, Helena
A1  - Castro-Luna, Alejandro A.
A1  - Cerda, Rolando
A1  - Cerezo, Alexis
A1  - Chauvat, Matthieu
A1  - Clarke, Frank M.
A1  - Cleary, Daniel F. R.
A1  - Connop, Stuart P.
A1  - D'Aniello, Biagio
A1  - da Silva, Pedro Giovani
A1  - Darvill, Ben
A1  - Dauber, Jens
A1  - Dejean, Alain
A1  - Diekötter, Tim
A1  - Dominguez-Haydar, Yamileth
A1  - Dormann, Carsten F.
A1  - Dumont, Bertrand
A1  - Dures, Simon G.
A1  - Dynesius, Mats
A1  - Edenius, Lars
A1  - Elek, Zoltán
A1  - Entling, Martin H.
A1  - Farwig, Nina
A1  - Fayle, Tom M.
A1  - Felicioli, Antonio
A1  - Felton, Annika M.
A1  - Ficetola, Gentile F.
A1  - Filgueiras, Bruno K. C.
A1  - Fonte, Steve J.
A1  - Fraser, Lauchlan H.
A1  - Fukuda, Daisuke
A1  - Furlani, Dario
A1  - Ganzhorn, Jörg U.
A1  - Garden, Jenni G.
A1  - Gheler-Costa, Carla
A1  - Giordani, Paolo
A1  - Giordano, Simonetta
A1  - Gottschalk, Marco S.
A1  - Goulson, Dave
A1  - Gove, Aaron D.
A1  - Grogan, James
A1  - Hanley, Mick E.
A1  - Hanson, Thor
A1  - Hashim, Nor R.
A1  - Hawes, Joseph E.
A1  - Hébert, Christian
A1  - Helden, Alvin J.
A1  - Henden, John-André
A1  - Hernández, Lionel
A1  - Herzog, Felix
A1  - Higuera-Diaz, Diego
A1  - Hilje, Branko
A1  - Horgan, Finbarr G.
A1  - Horváth, Roland
A1  - Hylander, Kristoffer
A1  - Horváth, Roland
A1  - Isaacs-Cubides, Paola
A1  - Ishitani, Mashiro
A1  - Jacobs, Carmen T.
A1  - Jaramillo, Victor J.
A1  - Jauker, Birgit
A1  - Jonsell, Matts
A1  - Jung, Thomas S.
A1  - Kapoor, Vena
A1  - Kati, Vassiliki
A1  - Katovai, Eric
A1  - Kessler, Michael
A1  - Knop, Eva
A1  - Kolb, Annette
A1  - Körösi, Àdám
A1  - Lachat, Thibault
A1  - Lantschner, Victoria
A1  - Le Féon, Violette
A1  - LeBuhn, Gretchen
A1  - Légaré, Jean-Philippe
A1  - Letcher, Susan G.
A1  - Littlewood, Nick A.
A1  - López-Quintero, Carlos A.
A1  - Louhaichi, Mounir
A1  - Lövei, Gabor L.
A1  - Lucas-Borja, Manuel Esteban
A1  - Luja, Victor H.
A1  - Maeto, Kaoru
A1  - Magura, Tibor
A1  - Mallari, Neil Aldrin
A1  - Marin-Spiotta, Erika
A1  - Marhall, E. J. P.
A1  - Martínez, Eliana
A1  - Mayfield, Margaret M.
A1  - Mikusinski, Gregorz
A1  - Milder, Jeffery C.
A1  - Miller, James R.
A1  - Morales, Carolina L.
A1  - Muchane, Mary N.
A1  - Muchane, Muchai
A1  - Naidoo, Robin
A1  - Nakamura, Akihiro
A1  - Naoe, Shoji
A1  - Nates-Parra, Guiomar
A1  - Navarerete Gutierrez, Dario A.
A1  - Neuschulz, Eike L.
A1  - Noreika, Norbertas
A1  - Norfolk, Olivia
A1  - Noriega, Jorge Ari
A1  - Nöske, Nicole M.
A1  - O'Dea, Niall
A1  - Oduro, William
A1  - Ofori-Boateng, Caleb
A1  - Oke, Chris O.
A1  - Osgathorpe, Lynne M.
A1  - Paritsis, Juan
A1  - Parrah, Alejandro
A1  - Pelegrin, Nicolás
A1  - Peres, Carlos A.
A1  - Persson, Anna S.
A1  - Petanidou, Theodora
A1  - Phalan, Ben
A1  - Philips, T. Keith
A1  - Poveda, Katja
A1  - Power, Eileen F.
A1  - Presley, Steven J.
A1  - Proença, Vânia
A1  - Quaranta, Marino
A1  - Quintero, Carolina
A1  - Redpath-Downing, Nicola A.
A1  - Reid, J. Leighton
A1  - Reis, Yana T.
A1  - Ribeiro, Danilo B.
A1  - Richardson, Barbara A.
A1  - Richardson, Michael J.
A1  - Robles, Carolina A.
A1  - Römbke, Jörg
A1  - Romero-Duque, Luz Piedad
A1  - Rosselli, Loreta
A1  - Rossiter, Stephen J.
A1  - Roulston, T'ai H.
A1  - Rousseau, Laurent
A1  - Sadler, Jonathan P.
A1  - Sáfián, Szbolcs
A1  - Saldaña-Vásquez, Romeo A.
A1  - Samnegård, Ulrika
A1  - Schüepp, Christof
A1  - Schweiger, Oliver
A1  - Sedlock, Jodi L.
A1  - Shahabuddin, Ghazala
A1  - Sheil, Douglas
A1  - Silva, Fernando A. B.
A1  - Slade, Eleanor
A1  - Smith-Pardo, Allan H.
A1  - Sodhi, Navjot S.
A1  - Somarriba, Eduardo J.
A1  - Sosa, Ramón A.
A1  - Stout, Jane C.
A1  - Struebig, Matthew J.
A1  - Sung, Yik-Hei
A1  - Threlfall, Caragh G.
A1  - Tonietto, Rebecca
A1  - Tóthmérész, Béla
A1  - Tscharntke, Teja
A1  - Turner, Edgar C.
A1  - Tylianakis, Jason M.
A1  - Vanbergen, Adam J.
A1  - Vassilev, Kiril
A1  - Verboven, Hans A. F.
A1  - Vergara, Carlos H.
A1  - Vergara, Pablo M.
A1  - Verhulst, Jort
A1  - Walker, Tony R.
A1  - Wang, Yanping
A1  - Watling, James I.
A1  - Wells, Konstans
A1  - Williams, Christopher D.
A1  - Willig, Michael R.
A1  - Woinarski, John C. Z.
A1  - Wolf, Jan H. D.
A1  - Woodcock, Ben A.
A1  - Yu, Douglas W.
A1  - Zailsev, Andreys
A1  - Collen, Ben
A1  - Ewers, Rob M.
A1  - Mace, Georgina M.
A1  - Purves, Drew W.
A1  - Scharlemann, Jörn P. W.
A1  - Pervis, Andy
T1  - The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts
JF  - Ecology and Evolution
N2  - Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - ). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
KW  - urban-rural gradient
KW  - instensively managed farmland
KW  - Mexican coffee plantations
KW  - Bombus Spp. Hymenoptera
KW  - bumblebee nest density
KW  - data sharing
KW  - land use
KW  - habitat destruction
KW  - global change
KW  - land-use change
KW  - plant community composition
KW  - Northeastern Costa Rica
KW  - dung beetle coleoptera
KW  - bird species richness
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114425
VL  - 4
IS  - 24
ER  - 
TY  - THES
A1  - Reis, Felix
T1  - Realization and Spectroscopy of the Quantum Spin Hall Insulator Bismuthene on Silicon Carbide
T1  - Realisierung und Spektroskopie des Quanten-Spin-Hall-Isolators Bismuten auf Siliziumkarbid
N2  - Topological matter is one of the most vibrant research fields of contemporary solid state physics since the theoretical prediction of the quantum spin Hall effect in graphene in 2005. Quantum spin Hall insulators possess a vanishing bulk conductivity but symmetry-protected, helical edge states that give rise to dissipationless charge transport. 
The experimental verification of this exotic state of matter in 2007 lead to a boost of research activity in this field, inspired by possible ground-breaking future applications. 
However, the use of the quantum spin Hall materials available to date is limited to cryogenic temperatures owing to their comparably small bulk band gaps. 

In this thesis, we follow a novel approach to realize a quantum spin Hall material with a large energy gap and epitaxially grow bismuthene, i.e., Bi atoms adopting a honeycomb lattice, in a \((\sqrt{3}\times\sqrt{3})\) reconstruction on the semiconductor SiC(0001). In this way, we profit both from the honeycomb symmetry as well as the large spin-orbit coupling of Bi, which, in combination, give rise to a topologically non-trivial band gap on the order of one electronvolt. 
An in-depth theoretical analysis demonstrates that the covalent bond between the Si and Bi atoms is not only stabilizing the Bi film but is pivotal to attain the quantum spin Hall phase. 

The preparation of high-quality, unreconstructed SiC(0001) substrates sets the basis for the formation of bismuthene and requires an extensive procedure in ultra-pure dry H\(_2\) gas. Scanning tunneling microscopy measurements unveil the (\(1\times1\)) surface periodicity and smooth terrace planes, which are suitable for the growth of single Bi layers by means of molecular beam epitaxy. The chemical configuration of the resulting Bi film and its oxidation upon exposure to ambient atmosphere are inspected with X-ray photoelectron spectroscopy. 

Angle-resolved photoelectron spectroscopy reveals the excellent agreement of probed and calculated band structure. In particular, it evidences a characteristic Rashba-splitting of the valence bands at the K point. Scanning tunneling spectroscopy probes signatures of this splitting, as well, and allows to determine the full band gap with a magnitude of \(E_\text{gap}\approx0.8\,\text{eV}\). 
Constant-current images and local-density-of-state maps confirm the presence of a planar honeycomb lattice, which forms several domains due to different, yet equivalent, nucleation sites of the (\(\sqrt{3}\times\sqrt{3}\))-Bi reconstruction. 

Differential conductivity measurements demonstrate that bismuthene edge states evolve at atomic steps of the SiC substrate. The probed, metallic local density of states is in agreement with the density of states expected from the edge state's energy dispersion found in density functional theory calculations - besides a pronounced dip at the Fermi level. 
By means of temperature- and energy-dependent tunneling spectroscopy it is shown that the spectral properties of this suppressed density of states are successfully captured in the framework of the Tomonaga-Luttinger liquid theory and most likely originate from enhanced electronic correlations in the edge channel.
N2  - Topologische Materie ist seit der Vorhersage des Quanten-Spin-Hall-Effekts in Graphen im Jahr 2005 eines der spannendsten Forschungsgebiete der gegenwärtigen Festkörperphysik. Quanten-Spin-Hall-Isolatoren besitzen zwar eine verschwindende Volumen-Leitfähigkeit, aber symmetriegeschützte, helikale Randzustände, welche verlustfreien Ladungstransport erlauben. 
Der 2007 erfolgte experimentelle Nachweis dieses außergewöhnlichen Materiezustands führte, inspiriert von möglicherweise bahnbrechenden zukünftigen Anwendungen, zu einem sprunghaften Anstieg der Forschungsaktivitäten auf diesem Gebiet. 
Jedoch ist der Nutzen der derzeit verfügbaren Quanten-Spin-Hall-Materialien aufgrund ihrer vergleichsweise kleinen Volumen-Bandlücken auf kryogene Temperaturen beschränkt. 

In dieser Arbeit verfolgen wir einen neuen Weg, ein Quanten-Spin-Hall-Material mit einer großen Energielücke zu realisieren und wachsen Bismuten, ein Honigwabengitter aus Bi-Atomen, epitaktisch in einer \((\sqrt{3}\times\sqrt{3})\)-Rekonstruktion auf den Halbleiter SiC(0001). 
Dadurch nutzen wir sowohl die Honigwaben-Symmetrie, als auch die große Spin-Bahn-Wechselwirkung von Bi aus, welche in Kombination zu einer topologisch nicht-trivialen Bandlücke in der Größenordnung eines Elektronenvolts führen. 
Eine eingehende theoretische Analyse zeigt, dass die kovalente Bindung zwischen den Si- und Bi-Atomen nicht nur den Bi-Film stabilisiert, sondern entscheidend zur Ausprägung der Quanten-Spin-Hall-Phase beiträgt. 

Die Präparation unrekonstruierter SiC(0001)-Substrate hoher Güte ist der Grundstein für das Bismutenwachstum und erfordert die Anwendung einer aufwändigen Prozedur in hochreinem, trockenem H\(_2\)-Gas. Messungen mit Rastertunnelmikroskopie enthüllen die (\(1\times1\))-Periodizität der Oberfläche und glatte Terrassenebenen, welche für das Aufwachsen einzelner Bi-Lagen mittels eines dedizierten Molekularstrahlepitaxieprozesses geeignet sind. 
Die chemische Konfiguration der Filme und ihre Oxidation nach Kontakt mit Umgebungsluft wird mit Röntgenphotoelektronenspektroskopie untersucht. 

Winkelaufgelöste Photoelektronenspektroskopie legt die exzellente Übereinstimmung zwischen gemessener und berechneter Bandstruktur offen. 
Insbesondere zeigt sie die charakteristische Rashba-Spinaufspaltung der Valenzbänder am K-Punkt. Messungen mit Rastertunnelspektroskopie beinhalten ebenso Hinweise dieser Aufspaltung, und ermöglichen die Bestimmung der vollständigen Größe der Bandlücke von \(E_\text{gap}\approx0.8\,\text{eV}\). Konstantstrom-Aufnahmen und Karten der lokalen Zustandsdichte bestätigen die Ausbildung eines planaren Honigwabengitters, welches aufgrund unterschiedlicher, jedoch äquivalenter Nukleationszentren der (\(\sqrt{3}\times\sqrt{3}\))-Bi-Rekonstruktion in mehreren Domänen auftritt. 

Messungen der differenziellen Leitfähigkeit offenbaren, dass sich Bismuten-Randzustände an atomaren Stufen des SiC-Substrats ausbilden. Die gemessene, lokale Zustandsdichte und die gemäß der Energiedispersion des Randzustands in Dichtefunktionaltheorierechnungen erwartete Zustandsdichte stimmen - abgesehen von einem starken Abfall am Fermi-Niveau - überein. 
Mit temperatur- und energieabhängiger Tunnelspektroskopie wird gezeigt, dass die spektralen Eigenschaften dieser unterdrückten Leitfähigkeit erfolgreich im Rahmen der Tomonaga-Luttinger-Flüssigkeitstheorie beschrieben und wahrscheinlich durch verstärkte elektronische Korrelationen im Randkanal ausgelöst werden.
KW  - Zweidimensionales Material
KW  - Topologischer Isolator
KW  - Siliziumcarbid
KW  - Rastertunnelmikroskopie
KW  - Photoelektronenspektroskopie
KW  - Bismuthene
KW  - Silicon Carbide
KW  - scanning tunneling spectroscopy
KW  - photoelectron spectroscopy
KW  - molecular beam epitaxy
KW  - quantum spin hall insulator
KW  - two-dimensional topological insulator
KW  - helical edge states
KW  - Luttinger liquid
KW  - honeycomb lattice
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258250
ER  -