Toward combined transport and optical studies of the 0.7‐anomaly in a quantum point contact. Issue 9 (16th April 2014)

• Record Type: Journal Article
• Authors: Schubert, Enrico; Heyder, Jan; Bauer, Florian; Waschneck, Bernd; Stumpf, Wolfgang; Wegscheider, Werner; von Delft, Jan; Ludwig, Stefan; Högele, Alexander; König, Jürgen; Oestreich, Michael
• Is Part Of: Physica status solidi. Volume 251:Issue 9(2014:Sep.)
• Page Start: 1931
• Page End: 1937
• Publication Date: 2014-04-16
• Subjects: Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201350218
• Languages: English
• ISSNs: 0370-1972

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="pssb201350218-sec-0001" sec-type="section"> <p>A quantum point contact (QPC) causes a one‐dimensional constriction on the spatial potential landscape of a two‐dimensional electron system. By tuning the voltage applied on the QPC gates which form the constriction at low temperatures the resulting regular step‐like electron conductance quantization can show an additional kink near pinch‐off around <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgh177xvmmm" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:15213951:media:pssb201350218:pssb201350218-math-0001" display="inline" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>0.7</mml:mn><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:mn>2</mml:mn><mml:msup><mml:mi>e</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:mrow><mml:mo>/</mml:mo><mml:mi>h</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:math></alternatives></inline-formula>, called 0.7‐anomaly. In a recent publication, we presented a combination of theoretical calculations and transport measurements that lead to a detailed understanding of the microscopic origin of the 0.7‐anomaly. Functional renormalization group‐based calculations were performed exhibiting the 0.7‐anomaly even when no symmetry‐breaking external magnetic fields are involved. According to the calculations the electron spin susceptibility is enhanced within a QPC that is tuned in the region of the 0.7‐anomaly. Moderate externally applied magnetic fields impose a corresponding enhancement in the spin magnetization. In principle, it should be possible to map out this spin distribution optically by means of the Faraday rotation technique. Here we report the initial steps of an experimental project aimed at realizing such measurements. Simulations were performed for a heterostructure designed to combine transport and optical studies. Based on the simulation results a sample was built and its basic transport and optical properties were investigated.</p> </sec> </abstract>