scholarly journals Introducing directionality to Anderson localization: The transport properties of quantum railroads

1994 ◽  
Vol 72 (9-10) ◽  
pp. 559-567 ◽  
Author(s):  
C. Barnes ◽  
B. L. Johnson ◽  
G. Kirczenow
Keyword(s):  
Hall Effect ◽  
Transport Properties ◽  
Quantum Hall Effect ◽  
Anderson Localization ◽  
Quantum Hall ◽  
Interference Effects ◽  
Mechanical Wave ◽  
Integer Quantum Hall Effect ◽  
Wave Guides ◽  
Integer Quantum

We present a study of the transport properties of a general class of quantum mechanical wave guides: quantum railroads (QRR). These wave guides are characterized by having adiabatic modes that carry current along the wave guide in opposite directions; for example N forward modes and M reverse modes. Anderson localization and the integer quantum Hall effect are characteristic of the disordered N = M and M = 0 cases, respectively. We consider the general case of arbitrary N and M, and show that it can be understood in terms of directed localization. Thus, we unify the theories of Anderson localization and the integer quantum Hall effect and demonstrate how they fit into a broader conceptual framework. We find that in any QRR there are always [Formula: see text] perfectly transmitted effective adiabatic modes with the remainder being subject to multiple scattering and interference effects characteristic of the N = M case.

scholarly journals An all-epitaxial nitride heterostructure with concurrent quantum Hall effect and superconductivity

2021 ◽  
Vol 7 (8) ◽  
pp. eabf1388
Author(s):  
Phillip Dang ◽  
Guru Khalsa ◽  
Celesta S. Chang ◽  
D. Scott Katzer ◽  
Neeraj Nepal ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Electron Gas ◽  
Quantum Hall ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
2D Electron Gas ◽  
Integer Quantum Hall Effect ◽  
Topological Quantum ◽  
Integer Quantum

Creating seamless heterostructures that exhibit the quantum Hall effect and superconductivity is highly desirable for future electronics based on topological quantum computing. However, the two topologically robust electronic phases are typically incompatible owing to conflicting magnetic field requirements. Combined advances in the epitaxial growth of a nitride superconductor with a high critical temperature and a subsequent nitride semiconductor heterostructure of metal polarity enable the observation of clean integer quantum Hall effect in the polarization-induced two-dimensional (2D) electron gas of the high-electron mobility transistor. Through individual magnetotransport measurements of the spatially separated GaN 2D electron gas and superconducting NbN layers, we find a small window of magnetic fields and temperatures in which the epitaxial layers retain their respective quantum Hall and superconducting properties. Its analysis indicates that in epitaxial nitride superconductor/semiconductor heterostructures, this window can be significantly expanded, creating an industrially viable platform for robust quantum devices that exploit topologically protected transport.

Publisher’s Note: Charge Fractionalization in the Integer Quantum Hall Effect [Phys. Rev. Lett. 112, 166801 (2014)]

2014 ◽  
Vol 112 (18) ◽  
Author(s):  
Hiroyuki Inoue ◽  
Anna Grivnin ◽  
Nissim Ofek ◽  
Izhar Neder ◽  
Moty Heiblum ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Integer Quantum Hall Effect ◽  
Integer Quantum ◽  
Charge Fractionalization
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