cannot load jquery datatable from controller?

This is my laravel controller to return data in jason format.data returns perfectly.but cannot load the datatable with return value.please help. i am stuck here for 2 days.

    public function doctors_appointment(Request $request){
    $doctor_id=$request->input('doctorid');
    $serial_date=Carbon::today()->toDateTimeString();
    $query = DB::table('serial_in_queues')
        ->select([DB::raw('MAX(patient_serial_no) AS patient_serial_no'), 
    DB::raw('MAX(patient_serial_time) AS patient_serial_time')])
        ->where([['doctors_id', '=', $doctor_id],
               ['patient_serial_date','=','2018-01-25']])
             ->groupBy('doctors_id')->get()->first();$data=array(array('patient_serial_time'=>$query>patient_serial_time,'dt'=>0));return json_encode($data);
}

my Ajax:

        $(document).ready(function () {
        $('#autocomplete-custom-append').autocomplete({
            serviceUrl: '',
            onSelect: function (suggestions) {
                $('#doctors_id').val(suggestions.data);

                var doctor_id = suggestions.data;
                var table = $('#time-slot').DataTable({
                    retrieve: true,
                    paginate: false,
                    sort: false,
                    info: false,
                    filter: false,
                    serverSide: true,
                    ajax: {
                        type: 'GET',
                        url: 'doctorAppointment',
                        dataType: 'json',
                        data: {doctorid: doctor_id},
                        success:function (data) {
                            console.log(data);
                            alert(data[0].patient_serial_time);
                            columns:[
                                {"data":"data[0].patient_serial_time"}
                            ]
                        }
                    },
                })
             }
        })
    })

via Chebli Mohamed