arXiv subjects

Jesse Kanter

Publications and source records attributed to Jesse Kanter.

4 recordsLinked to original sources

arXiv2022

Oxygen vacancy-induced anomalous Hall effect in a nominally non-magnetic oxide

The anomalous Hall effect, a hallmark of broken time-reversal symmetry and spin-orbit coupling, is frequently observed in magnetically polarized systems. Its realization in non-magnetic systems, however, remains elusive. Here, we report on the observation of anomalous Hall effect in nominally non-magnetic KTaO3. Anomalous Hall effect emerges in reduced KTaO3 and shows an extrinsic to intrinsic crossover. A paramagnetic behavior is observed in reduced samples using first principles calculations and quantitative magnetometry. The observed anomalous Hall effect follows the oxygen vacancy-induced magnetization response, suggesting that the localized magnetic moments of the oxygen vacancies scatter conduction electrons asymmetrically and give rise to anomalous Hall effect. The anomalous Hall conductivity becomes insensitive to scattering rate in the low temperature limit (T<5 K), implying that the Berry curvature of the electrons on the Fermi surface controls the anomalous Hall effect. Our observations describe a detailed picture of many-body interactions, triggering anomalous Hall effect in a non-magnetic system.

cond-mat.mes-hall↗

arXiv2022

Induced superconducting pairing in integer quantum Hall edge states

Indium Arsenide (InAs) near surface quantum wells (QWs) are promising for the fabrication of semiconductor-superconductor heterostructures given that they allow for a strong hybridization between the two-dimensional states in the quantum well and the ones in the superconductor. In this work we present results for InAs QWs in the quantum Hall regime placed in proximity of superconducting NbTiN. We observe a negative downstream resistance with a corresponding reduction of Hall (upstream) resistance, consistent with a very high Andreev conversion. We analyze the experimental data using the Landauer-Büttiker formalism, generalized to allow for Andreev reflection processes. We attribute the high efficiency of Andreev conversion in our devices to the large transparency of the InAs/NbTiN interface and the consequent strong hybridization of the QH edge modes with the states in the superconductor.

cond-mat.mes-hall↗

arXiv2021

Coexistence of superconductivity and weak anti-localization at KTaO3 (111) interfaces

The intersection of two-dimensional superconductivity and topologically nontrivial states hosts a wide range of quantum phenomena, including Majorana fermions. Coexistence of topologically nontrivial states and superconductivity in a single material, however, remains elusive. Here, we report on the observation of two-dimensional superconductivity and weak anti-localization at the TiOx/KTaO3(111) interfaces. A remnant, saturating resistance persists below the transition temperature as superconducting puddles fail to reach phase coherence. Signatures of weak anti-localization are observed below the superconducting transition, suggesting the coexistence of superconductivity and weak anti-localization. The superconducting interfaces show roughly one order of magnitude larger weak anti-localization correction, compared to non-superconducting interfaces, alluding to a relatively large coherence length in these interfaces.

cond-mat.supr-con↗

arXiv2016

Magneto-intersubband resistance oscillations in GaAs quantum wells placed in a tilted magnetic field

The magnetotransport of highly mobile 2D electrons in wide GaAs single quantum wells with three populated subbands placed in titled magnetic fields is studied. The bottoms of the lower two subbands have nearly the same energy while the bottom of the third subband has a much higher energy ($E_1\approx E_2<<E_3$). At zero in-plane magnetic fields magneto-intersubband oscillations (MISO) between the $i^{th}$ and $j^{th}$ subbands are observed and obey the relation $Δ_{ij}=E_j-E_i=k\cdot\hbarω_c$, where $ω_c$ is the cyclotron frequency and $k$ is an integer. An application of in-plane magnetic field produces dramatic changes in MISO and the corresponding electron spectrum. Three regimes are identified. At $\hbarω_c \ll Δ_{12}$ the in-plane magnetic field increases considerably the gap $Δ_{12}$, which is consistent with the semi-classical regime of electron propagation. In contrast at strong magnetic fields $\hbarω_c \gg Δ_{12}$ relatively weak oscillating variations of the electron spectrum with the in-plane magnetic field are observed. At $\hbarω_c \approx Δ_{12}$ the electron spectrum undergoes a transition between these two regimes through magnetic breakdown. In this transition regime MISO with odd quantum number $k$ terminate, while MISO corresponding to even $k$ evolve $continuously$ into the high field regime corresponding to $\hbarω_c \gg Δ_{12}$

cond-mat.mes-hall↗