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Magnetoresistance anomalies resulting from Stark resonances in semiconductor nanowires with a constriction
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2014 J. Phys.: Condens. Matter 26 325301 (http://iopscience.iop.org/0953-8984/26/32/325301) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 129.81.226.78 This content was downloaded on 22/08/2014 at 11:45
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Journal of Physics: Condensed Matter J. Phys.: Condens. Matter 26 (2014) 325301 (10pp)
doi:10.1088/0953-8984/26/32/325301
Magnetoresistance anomalies resulting from Stark resonances in semiconductor nanowires with a constriction M Wołoszyn, B J Spisak, J Adamowski and P Wójcik AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Krakow, Poland E-mail: [email protected] and [email protected] Received 17 February 2014, revised 27 May 2014 Accepted for publication 10 June 2014 Published 16 July 2014 Abstract
Magnetotransport properties of a semiconductor nanowire with a constriction have been studied within the Landauer–Büttiker formalism in the presence of the axially oriented magnetic field at low temperatures. The one-electron quantum states in the nanowire have been calculated within the adiabatic approximation which takes into account the threedimensional structure of the nanowire and allows us to study the effect of the transverse quantum states on the electronic current. The calculated current-voltage characteristics exhibit well pronounced peaks that result from the enhancement of the electron transmission by the Stark resonant states formed in the triangular quantum well near the constriction. The effect of the Stark resonances is clearly manifested in the magnetoresistance as a function of the drain-source voltage. The calculated magnetoresistance exhibits two interesting features: (i) rapid jumps at certain voltages, caused by the enhancement of the electron transmission by the Stark resonances, (ii) changes of sign that stem from the magnetic-field induced changes of the current-voltage characteristics slope. The influence of the constriction parameters (radius, length, smoothness of the potential barrier, position of the constriction in the nanowire) on the electronic current has also been analyzed. Since the effective potential barrier created by the constriction in the nanowire is similar to that generated by the negatively charged gate surrounding the nanowire, the presented results can also be applied to the description of the magnetoresistance in the gated nanowires. Keywords: quantum wires, magnetotransport, ballistic transport (Some figures may appear in colour only in the online journal)
1. Introduction
size of the nanostructure L. The relationships between these characteristic lengths determine the different regimes of the electronic transport in the nanostructures. One of them is the ballistic regime that is defined by the inequalities: λF
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Magnetoresistance anomalies resulting from Stark resonances in semiconductor nanowires with a constriction
This content has been downloaded from IOPscience. Please scroll down to see the full text. 2014 J. Phys.: Condens. Matter 26 325301 (http://iopscience.iop.org/0953-8984/26/32/325301) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 129.81.226.78 This content was downloaded on 22/08/2014 at 11:45
Please note that terms and conditions apply.
Journal of Physics: Condensed Matter J. Phys.: Condens. Matter 26 (2014) 325301 (10pp)
doi:10.1088/0953-8984/26/32/325301
Magnetoresistance anomalies resulting from Stark resonances in semiconductor nanowires with a constriction M Wołoszyn, B J Spisak, J Adamowski and P Wójcik AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Krakow, Poland E-mail: [email protected] and [email protected] Received 17 February 2014, revised 27 May 2014 Accepted for publication 10 June 2014 Published 16 July 2014 Abstract
Magnetotransport properties of a semiconductor nanowire with a constriction have been studied within the Landauer–Büttiker formalism in the presence of the axially oriented magnetic field at low temperatures. The one-electron quantum states in the nanowire have been calculated within the adiabatic approximation which takes into account the threedimensional structure of the nanowire and allows us to study the effect of the transverse quantum states on the electronic current. The calculated current-voltage characteristics exhibit well pronounced peaks that result from the enhancement of the electron transmission by the Stark resonant states formed in the triangular quantum well near the constriction. The effect of the Stark resonances is clearly manifested in the magnetoresistance as a function of the drain-source voltage. The calculated magnetoresistance exhibits two interesting features: (i) rapid jumps at certain voltages, caused by the enhancement of the electron transmission by the Stark resonances, (ii) changes of sign that stem from the magnetic-field induced changes of the current-voltage characteristics slope. The influence of the constriction parameters (radius, length, smoothness of the potential barrier, position of the constriction in the nanowire) on the electronic current has also been analyzed. Since the effective potential barrier created by the constriction in the nanowire is similar to that generated by the negatively charged gate surrounding the nanowire, the presented results can also be applied to the description of the magnetoresistance in the gated nanowires. Keywords: quantum wires, magnetotransport, ballistic transport (Some figures may appear in colour only in the online journal)
1. Introduction
size of the nanostructure L. The relationships between these characteristic lengths determine the different regimes of the electronic transport in the nanostructures. One of them is the ballistic regime that is defined by the inequalities: λF
