Transport through a quantum spin Hall quantum dot

Quantum spin Hall insulators, recently realized in HgTe/(Hg,Cd)Te quantum wells, support topologically protected, linearly dispersing edge states with spin-momentum locking. A local magnetic exchange field can open a gap for the edge states. A quantum-dot structure consisting of two such magnetic tunneling barriers is proposed and the charge transport through this device is analyzed. The effects of a finite bias voltage beyond linear response, of a gate voltage, and of the charging energy in the quantum dot are studied within a combination of Green-function and master-equation approaches. Among other results, a partial recurrence of non-interacting behavior is found for strong interactions, and the possibility of controlling the edge magnetization by a locally applied gate voltage is proposed.Comment: 12 pages, 7 figure

Country Inequality Rankings and Conversion Schemes

Two conversion schemes are usually employed for assessing personal-income inequality from household equivalent incomes: to weight household units by size or by needs.Using data from the Luxembourg Income Study, we show the sensitivity of country inequality rankings to conversion schemes and explain the finding by means of inequality decomposition. A bootstrap approach is implemented to test for statistical significance of our results.inequality, equivalence scale, equivalent income, weighting scheme,decomposition

The German spatial poverty divide: poorly endowed or bad luck?

We study inter-temporal changes in poverty for Germany from year 1978 to 2003, and we employ the bootstrap method to test for statistical significance of results. All results are decomposed by household type and region. Poverty estimates are particularly high for single parents. Most striking, however, is the poverty divide between the old and newly-formed German Federal States, with poverty being significantly higher in the latter. We conduct a nonlinear Oaxaca-Blinder decomposition to quantify the separate contribution of regional differences in households’ characteristics to the probability of being poor.Poverty, decomposition, expenditure patterns, necessities, Oaxaca-Blinder decomposition, bootstrap, equivalence scale.