Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

• Samuel D. Escribano,
• Alfredo Levy Yeyati and
• Elsa Prada

Beilstein J. Nanotechnol. 2018, 9, 2171–2180, doi:10.3762/bjnano.9.203

• , Universidad Autónoma de Madrid, E-28049 Madrid, Spain 10.3762/bjnano.9.203 Abstract Majorana modes emerge in non-trivial topological phases at the edges of specific materials such as proximitized semiconducting nanowires under an external magnetic field. Ideally, they are non-local states that are charge

• -dimensional model of the dielectric surroundings, here we show that, under certain circumstances, these interactions lead to a suppression of the Majorana oscillations predicted by simpler theoretical models, and to the formation of low-energy quantum-dot states that interact with the Majorana modes. Both

• smaller inside the wire than in the reservoirs, a repulsive interaction is produced between the incoming charge and its images, preventing its entrance. This translates into finite regions in parameter space (in red in Figure 1b) where Majorana modes are pinned to zero energy within a finite range of VZ

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• discontinuities and ground-state parity crossings [55][56][57][58][59][60][61] have been recognized as precursors of Majorana modes in the long-wire limit [27][50], and of Floquet–Majorana modes realized in driven quantum dots [62][63]. We will analytically derive and discuss the spectrum and the Josephson

Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

• Tudor D. Stanescu,
• Anna Sitek and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1512–1526, doi:10.3762/bjnano.9.142

• systems is motivated, in part, by the perspective of using them as a platform for fault-tolerant topological quantum computation [1][2][3][4]. Several practical realizations of “synthetic” topological superconductors that host zero-energy Majorana modes have been proposed in the past few years, the most

• longitudinal magnetic field. The system is predicted to host zero-energy Majorana modes localized at the two ends of the nanowire [5][7][8]. These zero-energy states combine equal proportions of electrons and holes and are created by second quantized operators satisfying the “Majorana condition” γ† = γ. The

• stability of the Majorana modes [28]. Proximitized core–shell nanowires are slightly more complex systems recently shown [29] to have interesting Majorana physics that is practically immune to orbital effects. With a conductive shell and an insulating core, such heterostructures become tubular conductors

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• ↑ and ↓ spin sectors. This “intrinsic polarization” of the Majorana modes has been previously suggested in [46], and recently we have proposed [47] their empirical detection by means of selective equal-spin Andreev reflection (SESAR) spectroscopy. The main idea is to apply a bias voltage V between the

• attempting to braid the Majorana end modes, e.g., in T-shape nanowires upon turning on and off the topological superconducting phase in its segments. We briefly analyse here the polarized zero-energy Majorana modes leaking into the multi-site quantum dot (comprising ten lattice sites) side-attached to the

• , μ = −2t, Δi = 0.2t and B > Bc, which guarantee the Rashba chain to be in its topologically nontrivial superconducting phase, hosting the zero-energy Majorana quasiparticles (intensive black or red regions). We clearly observe that for some values of Vg these Majorana modes spread over the entire

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• interactions between the bound charges in the dielectric surroundings and the free charges in the nanowire [55], a finite leakage out of the Majorana modes due to the presence the normal drain [59], a finite coherence length in the induced superconducting pairing [60], and the orbital magnetic effects [61

• conductance peak spacing. This means that the Majorana energy splitting can not be genuinely characterized by the conductance signature. One possible reason is that the Majorana energy splitting is not robust. When the energy splitting of the Majorana modes is negligible compared to the magnitude of disorder

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• favored. Conclusion: Circular-dichroism spectroscopy of chiral Majorana states is suggested as a relevant probe for these peculiar states of topological matter. Keywords: chiral states; circular dichroism; Majorana modes; optical absorption; topological matter; Introduction The physics of Majorana

• states in condensed matter devices is attracting strong interest for a few years now [1][2][3][4][5][6][7][8]. The measured zero-bias conductance peaks in hybrid semiconductor/superconductor nanowires have been attributed to the presence of localized Majorana modes on the two ends of the nanowires [9][10

• quasiparticles, a class of hybrid systems where Majorana states appear around 2D vortex cores in the bulk and on the external edges of the sample [16]. Another class of 2D materials with propagating Majorana modes are the topological insulators based on the quantum-anomalous Hall effect. We refer, specifically