Magnetic Field Probing of an SU(4) Kondo Resonance in a Single Atom Transistor

Semiconductor nano-devices have been scaled to the level that transport can be dominated by a single dopant atom. In the strong coupling case a Kondo effect is observed when one electron is bound to the atom. Here, we report on the spin as well as orbital Kondo ground state. We experimentally as well than theoretically show how we can tune a symmetry transition from a SU(4) ground state, a many body state that forms a spin as well as orbital singlet by virtual exchange with the leads, to a pure SU(2) orbital ground state, as a function of magnetic field. The small size and the s-like orbital symmetry of the ground state of the dopant, make it a model system in which the magnetic field only couples to the spin degree of freedom and allows for observation of this SU(4) to SU(2) transition.Comment: 12 pages, 10 figures, accepted for publication in Physical Review Letter

Heterointerface effects on the charging energy of shallow D- ground state in silicon: the role of dielectric mismatch

Donor states in Si nanodevices can be strongly modified by nearby insulating barriers and metallic gates. We report here experimental results indicating a strong reduction in the charging energy of isolated As dopants in Si FinFETs relative to the bulk value. By studying the problem of two electrons bound to a shallow donor within the effective mass approach, we find that the measured small charging energy may be due to a combined effect of the insulator screening and the proximity of metallic gates.Comment: 7 pages, 6 figure

A hybrid double-dot in silicon

We report electrical measurements of a single arsenic dopant atom in the tunnel-barrier of a silicon SET. As well as performing electrical characterization of the individual dopant, we study series electrical transport through the dopant and SET. We measure the triple points of this hybrid double dot, using simulations to support our results, and show that we can tune the electrostatic coupling between the two sub-systems.Comment: 11 pages, 6 figure

Single donor ionization energies in a nanoscale CMOS channel

One consequence of the continued downwards scaling of transistors is the reliance on only a few discrete atoms to dope the channel, and random fluctuations of the number of these dopants is already a major issue in the microelectonics industry. While single-dopant signatures have been observed at low temperature, studying the impact of only one dopant up to room temperature requires extremely small lengths. Here, we show that a single arsenic dopant dramatically affects the off-state behavior of an advanced microelectronics field effect transistor (FET) at room temperature. Furthermore, the ionization energy of this dopant should be profoundly modified by the close proximity of materials with a different dielectric constant than the host semiconductor. We measure a strong enhancement, from 54meV to 108meV, of the ionization energy of an arsenic atom located near the buried oxide. This enhancement is responsible for the large current below threshold at room temperature and therefore explains the large variability in these ultra-scaled transistors. The results also suggest a path to incorporating quantum functionalities into silicon CMOS devices through manipulation of single donor orbitals

Tunable Kondo effect in a single donor atom

The Kondo effect has been observed in a single gate-tunable atom. The measurement device consists of a single As dopant incorporated in a Silicon nanostructure. The atomic orbitals of the dopant are tunable by the gate electric field. When they are tuned such that the ground state of the atomic system becomes a (nearly) degenerate superposition of two of the Silicon valleys, an exotic and hitherto unobserved valley Kondo effect appears. Together with the regular spin Kondo, the tunable valley Kondo effect allows for reversible electrical control over the symmetry of the Kondo ground state from an SU(2)- to an SU(4) -configuration.Comment: 10 pages, 8 figure

PENYALAHGUNAAN ASET NEGARA DALAM BENTUK JARINGAN SATELIT UNTUK KEPENTINGAN KORPORASI DIHUBUNGKAN DENGAN UNDANGUNDANG NOMOR 36 TAHUN 1999 TENTANG TELEKOMUNIKASI JO UNDANGUNDANG NOMOR 20 TAHUN 2001 TENTANG TINDAK PIDANA KORUPSI

telekomunikasi sebagaimana dilakukan oleh IM2. IM2 telah menyalahgunakan pita frekuensi 2.1 Ghz, dan secara melawan hukum beroperasi pada jaringan tersebut sehingga menimbulkan kerugian negara. Berdasarkan hal tersebut maka penulis tertarik meneliti, bagaimana Undang-Undang Telekomunikasi jo Peraturan Menteri Komunikasi dan Informatika dan Undang-Undang Tindak Pidana Korupsi mengatur mekanisme pemanfaatan aset negara berupa jaringan satelit, mengapa aset negara berupa jaringan satelit kerap kali disalahgunakan didalam pemanfaatannya oleh korporasi, serta bagaimana upaya yang dapat dilakukan untuk melindungi aset negara dalam bentuk jaringan satelit terhadap penyalahgunaan yang dilakukan oleh korporasi. Penelitian ini menggunakan spesifikasi penelitian yang bersifat deskriftif analitis dengan pendekatan yuridis normatif dibantu yuridis empiris, data yang diperlukan dalam penelitian ini dikumpulkan melalui studi kepustakaan dan studi lapangan, kemudian dianalisis menggunakan teknik analisis data berupa yuridis kualitatif. Pemanfaatan aset negara berupa jaringan satelit melalui pita frekuensi merupakan salah satu hak yang dalam pemanfaatannya diatur oleh peraturan perundang-undangan agar tercipta keadilan, kepastian dan ketertiban, keamanan, keseimbangan, perlindungan dan pemeliharaan dalam pemanfataannya. Jaringan satelit yang merupakan jaringan satelit aset negara pemanfaatannya mensyaratkan izin dan pembayaran tarif tertentu, sehingga konsekuensinya ketika terjadi penyalahgunaan pemanfaatan jaringan satelit, negara akan mengalami kerugian. Aset negara berupa jaringan satelit kerap kali disalahgunakan didalam pemanfaatannya oleh korporasi disebabkan beberapa faktor diantaranya faktor hukum itu sendiri dalam hal ini peraturan perundang-undangannya, faktor penegak hukum, faktor sarana atau fasilitas yang mendukung pengawasan dan penegakan hukum itu sendiri, faktor masyarakat, yakni lingkungan dimana hukum tersebut berlaku atau diterapkan, dalam hal ini yaitu lingkungan korporasi, faktor kebudayaan yakni kurangnya kesadaran hukum korporasi dalam upaya pemanfaatan aset negara secara berkeadilan dan tertib sesuai peraturan perundang-undangan yang berlaku, dimana pemanfaatan yang tidak secara berkeadilan akan membawa negara menuju kepada kehancuran. Upaya yang dapat dilakukan untuk melindungi aset negara dalam bentuk jaringan satelit terhadap penyalahgunaan yang dilakukan oleh korporasi harus berangkat dari beberapa faktor yang menjadi penyebab penyalahgunaan pemanfaatan jaringan satelit diantaranya yaitu melalui upaya preventif berupa revisi perunang-undangan, pengawasan, sosialisasi sert upaya represif berupa penegakan hukum. Penegakan hukum harus dilaksanakan tanpa pandang bulu, sebagai bentuk keyakinan atas doktrin hukum, bahwa setiap orang mempunyai kedudukan yang sama di depan hukum. Kata Kunci: Penyalahgunaan Aset Negara, Jaringan Sateli

ADHD and EEG-neurofeedback: a double-blind randomized placebo-controlled feasibility study

Electroencephalography (EEG)-neurofeedback has been shown to offer therapeutic benefits to patients with attention-deficit/hyperactivity disorder (ADHD) in several, mostly uncontrolled studies. This pilot study is designed to test the feasibility and safety of using a double-blind placebo feedback-controlled design and to explore the initial efficacy of individualized EEG-neurofeedback training in children with ADHD. Fourteen children (8–15 years) with ADHD defined according to the DSM-IV-TR criteria were randomly allocated to 30 sessions of EEG-neurofeedback (n = 8) or placebo feedback (n = 6). Safety measures (adverse events and sleep problems), ADHD symptoms and global improvement were monitored. With respect to feasibility, all children completed the study and attended all study visits and training sessions. No significant adverse effects or sleep problems were reported. Regarding the expectancy, 75% of children and their parent(s) in the active neurofeedback group and 50% of children and their parent(s) in the placebo feedback group thought they received placebo feedback training. Analyses revealed significant improvements of ADHD symptoms over time, but changes were similar for both groups. This pilot study shows that it is feasible to conduct a rigorous placebo-controlled trial to investigate the efficacy of neurofeedback training in children with ADHD. However, a double-blind design may not be feasible since using automatic adjusted reward thresholds may not work as effective as manually adjusted reward thresholds. Additionally, implementation of active learning strategies may be an important factor for the efficacy of EEG-neurofeedback training. Based on the results of this pilot study, changes are made in the design of the ongoing study

Bicaudal D2, Dynein, and Kinesin-1 Associate with Nuclear Pore Complexes and Regulate Centrosome and Nuclear Positioning during Mitotic Entry

Mammalian Bicaudal D2 is the missing molecular link between cytoplasmic motor proteins and the nucleus during nuclear positioning prior to the onset of mitosis