Topological invariant for two-dimensional open systems

Zheng, Jun-Hui; Hofstetter, Walter

doi:10.1103/physrevb.97.195434

Cited by 25 publications

(25 citation statements)

References 51 publications

(66 reference statements)

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“…Berry curvature of quasi-particle state and localized states: The GIMF can be expressed as the summation of the Berry curvature of all occupied quasi-particle states, following the contour-integration method developed in Refs. [53,54]. The GIMF becomes…”

Section: Hall Conductance In the Extended Infinite Systemmentioning

confidence: 99%

Interaction-enhanced integer quantum Hall effect in disordered systems

2019

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We study transport properties and topological phase transition in two-dimensional interacting disordered systems. Within dynamical mean-field theory, we derive the Hall conductance, which is quantized and serves as a topological invariant for insulators, even when the energy gap is closed by localized states. In the spinful Harper-Hofstadter-Hatsugai model, in the trivial insulator regime, we find that the repulsive on-site interaction can assist weak disorder to induce the integer quantum Hall effect, while in the topologically non-trivial regime, it impedes Anderson localization. Generally, the interaction broadens the regime of the topological phase in the disordered system. PACS numbers: xxThe quantum Hall effect (QHE) in the presence of interaction and disorder has been of great interest for a long time.Interactions play an essential role in the fractional QHE [1] and disorder is responsible for the existence of the plateaux in the Hall conductance [2][3][4][5]. For different models, the perfect quantization of conductance can be violated [6][7][8][9][10][11][12][13][14][15][16] or conversely induced [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] by disorder and interaction, respectively. Topological invariants are constructed to classify the resulting transport properties [33][34][35] in systems with bulk energy gaps. General expressions for the invariants of interacting and disordered systems were developed from the perspective of the many-body wave functions (MBW) [36][37][38][39]. Nonetheless, the MBW can be captured numerically only for a rather small size of the interacting system. Equivalent expressions in terms of the single-particle Green's function were developed thereafter, based on the microscopic theory [40][41][42], which are numerically accessible even for infinite systems if translational symmetry (TS) is assumed [43]. arXiv:1805.10491v2 [cond-mat.dis-nn]

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Section: Hall Conductance In the Extended Infinite Systemmentioning

confidence: 99%

Interaction-enhanced integer quantum Hall effect in disordered systems

2019

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“…It was observed that the higher T c phase appears more frequently in the Cu rich regions. One of the most intriguing features of the superconducting phase of PdTe 2 is that despite hosting topologically non-trivial bands crossing the Fermi surface [21,22], the superconducting order parameter is found to be conventional and is seen to follow BCS-like temperature dependence [13,23]. The conventional nature of the temperature dependence is also found in case of the two energy gaps that are measured in Cu-intercalated PdTe 2 .…”

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confidence: 98%

Enhanced, homogeneously type-II superconductivity in Cu-intercalated PdTe₂

Vasdev

Sirohi

Hooda

et al. 2019

J. Phys.: Condens. Matter

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Though the superconducting phase of the type-II Dirac semimetal PdTe2 was shown to be conventional in nature, the phase continued to be interesting in terms of its magnetic properties. While certain experiments indicated an unexpected type-I superconducting phase, other experiments revealed formation of vortices under the application of magnetic fields. Recently, scanning tunneling spectroscopy (STS) experiments revealed the existence of a mixed phase where type-I and type-II behaviours coexist. Here, based on our temperature and magnetic field dependent STS experiments on Cu-intercalated PdTe2 we show that as the critical temperature of the superconducting phase goes up from 1.7 K to 2.4 K on Cu-intercalation, the mixed phase disappears and the system becomes homogeneously type-II. This may be attributed to an averaging effect caused by quasiparticle exchange between type-I and type-II domains mediated by the Cu atoms and to decreased coherence length due to increased disorder.

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“…However, for large spin-orbit coupling γ ≈ 1/4 it fails combined with the LCM method. Moreover the density matrix method [41] fails because the density matrix becomes gapless. In contrast, here we consider the decoupled virtual spin system (6), and we apply the LCM to a single spin component.…”

Section: Fig 3 Local Compressibility Computed From Rdmft Resultsmentioning

confidence: 99%

Interacting Hofstadter Interface

2019

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Two-dimensional topological insulators possess conducting edge states at their boundary while being insulating in the bulk. The detection of edge states remains an open question in ultracold atom setups. We propose a configuration to implement a topological interface within the experimentally realizable time-reversal invariant Hofstadter model which gives rise to a topological phase boundary at the center of the system, and investigate the influence of two-body interactions on the interface in a fermionic system. The interface can in principle be probed via the spatially resolved compressibility of the system by using a quantum gas microscope. Furthermore, we distinguish the phases through their Hall response and compute a local spin Chern marker which proves the phase separation of two distinct topological many-body phases. The bulk-boundary correspondence for the interacting system is confirmed by computing the edge state spectra at the interface.

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Topological invariant for two-dimensional open systems

Cited by 25 publications

References 51 publications

Interaction-enhanced integer quantum Hall effect in disordered systems

Interaction-enhanced integer quantum Hall effect in disordered systems

Enhanced, homogeneously type-II superconductivity in Cu-intercalated PdTe₂

Interacting Hofstadter Interface

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Topological invariant for two-dimensional open systems

Cited by 25 publications

References 51 publications

Interaction-enhanced integer quantum Hall effect in disordered systems

Interaction-enhanced integer quantum Hall effect in disordered systems

Enhanced, homogeneously type-II superconductivity in Cu-intercalated PdTe2

Interacting Hofstadter Interface

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Enhanced, homogeneously type-II superconductivity in Cu-intercalated PdTe₂