Coherent tunnelling across a quantum point contact in the quantum Hall regime
نویسندگان
چکیده
The unique properties of quantum hall devices arise from the ideal one-dimensional edge states that form in a two-dimensional electron system at high magnetic field. Tunnelling between edge states across a quantum point contact (QPC) has already revealed rich physics, like fractionally charged excitations, or chiral Luttinger liquid. Thanks to scanning gate microscopy, we show that a single QPC can turn into an interferometer for specific potential landscapes. Spectroscopy, magnetic field and temperature dependences of electron transport reveal a quantitatively consistent interferometric behavior of the studied QPC. To explain this unexpected behavior, we put forward a new model which relies on the presence of a quantum Hall island at the centre of the constriction as well as on different tunnelling paths surrounding the island, thereby creating a new type of interferometer. This work sets the ground for new device concepts based on coherent tunnelling.
منابع مشابه
شبیه سازی اثر بی نظمی و میدان مغناطیسی بر ترابرد کوانتومی نانوساختارهای دو بعدی مدل شده با تقریب تنگابست
In recent years, semiconductor nanostructures have become the model systems of choice for investigation of electrical conduction on short length scales. Quantum transport is studied in a two dimensional electron gas because of the combination of a large Fermi wavelength and large mean free path. In the present work, a numerical method is implemented in order to contribute to the understanding ...
متن کاملDouble point contact in quantum Hall line junctions.
We show that multiple point contacts on a barrier separating two laterally coupled quantum Hall fluids induce Aharonov-Bohm (AB) oscillations in the tunneling conductance. These quantum coherence effects provide new evidence for the Luttinger liquid behavior of the edge states of quantum Hall fluids. For a two point contact, we identify coherent and incoherent regimes determined by the relative...
متن کاملExploring the fractional quantum Hall effect with electron tunneling
In this talk I present a summary of recent work on tunnel junctions of a fractional quantum Hall fluid and an electron reservoir, a Fermi liquid. I consider first the case of a single point contact. This is a an exactly solvable problem from which much can be learned. I also discuss in some detail how these solvable junction problems can be used to understand many aspects of the recent electron...
متن کاملSpectral noise for edge states at the filling factor
We present a detailed analysis of finite-frequency noise for the ν = 5/2 fractional quantum Hall state in a quantum point contact geometry. The results were obtained within the Pfaffian and anti-Pfaffian models. We show that the behaviour of the coloured noise allows us to unambiguously discriminate among tunnelling excitations with different charges. Optimal values of the external bias are fou...
متن کاملQuantum point contact between compressible Quantum Hall liquids
We elaborate on a theory of electronic transport through a quantum point contact (QPC) in the Quantum Hall (QH) regime, which does not discriminate between compressible and incompressible QH liquids, and accounts for both diffusive and ballistic regimes of the bulk electron motion. In either regime we find departures from the accustomed chiral Luttinger liquid behavior. The results suggest that...
متن کامل